Circulating lipids, lipid-lowering drug targets, and breast cancer risk: Comprehensive evidence from Mendelian randomization and summary data-based Mendelian randomization.

BACKGROUND: Breast cancer (BC) is the most common and fatal cancer among women, yet the causal relationship between circulating lipids, lipid-lowering drugs, and BC remains unclear. METHODS: Mendelian randomization (MR) and summary data-based MR (SMR) analysis are used to explore the causal relationship between plasma lipids, lipid-lowering drug targets, and BC. RESULTS: The result of MR suggested that per mg/dL higher levels of LDL-C (OR = 1.045, FDR = 0.023), HDL-C (OR = 1.079, FDR = 0.003), TC (OR = 1.043, FDR = 0.026), and APOA-I (OR = 1.085, FDR = 2.64E-04) were associated with increased BC risk, while TG was associated with reduced BC risk (OR = 0.926, FDR = 0.003). Per mg/dL higher levels of HDL-C (OR = 1.080, FDR = 0.011) and APOA-I (OR = 1.083, FDR = 0.002) were associated with increased ER+BC risk, while TG was associated with reduced ER+BC risk (OR = 0.909, FDR = 0.002). For every per 1 mg/dL decrease in LDL, HMGCR (OR: 0.839; FDR = 0.016), NPC1L1 (OR: 0.702; FDR = 0.004), and PCSK9 (OR: 0.916; FDR = 0.026) inhibition were associated with reduced BC risk, whereas CETP inhibition (OR: 1.194; FDR = 0.026) was associated with increased BC risk. For every per 1 mg/dL decrease in LDL, HMGCR (OR: 0.822; FDR = 0.023), NPC1L1 (OR: 0.633; FDR = 2.37E-03), and APOB inhibition (OR: 0.816; FDR = 1.98E-03) were associated with decreased ER-BC risk, while CETP inhibition (OR: 1.465; FDR = 0.011) was associated with increased ER-BC risk. SMR analysis indicated that HMGCR was associated with increased BC risk (OR: 1.112; p = 0.044). CONCLUSION: Lipids are associated with the BC risk, and lipid-lowering drugs targets HMGCR, NPC1L1, PCSK9, and APOB may be effective strategies for preventing BC. However, lipid-lowering drugs target CETP may potentially increase BC risk.

Noble metal-free SERS: mechanisms and applications.

Surface-enhanced Raman scattering (SERS) is a very important tool in vibrational spectroscopy. The coupling of nanomaterials induces local surface plasmon resonance (LSPR), which contributes greatly to SERS. Due to its remarkable sensitivity in trace detection, SERS has gained prominence in the fields of catalysis, biosensors, drug tracking, and optoelectronic devices. SERS activity is believed to be closely related to the LSPR and charge transfer (CT) of the material. Noble metal nanostructures have been commonly used as SERS-active substrates due to their strong local electric fields and relatively mature preparation, application, and enhancement mechanisms. In recent years, SERS research based on semiconductor materials has attracted significant attention because semiconductor materials have advantages such as repeatable preparation, simple pretreatment, stable SERS spectra and superior biocompatibility, stability, and reproducibility. Semiconductor-based SERS has the potential to enrich SERS theory and applications. Thus, the development of semiconductor materials will introduce a new epoch for SERS-based research. In this review, we outline the two main kinds of semiconductor SERS-active substrates: inorganic and organic semiconductor SERS-active substrates. We also provide an overview of the SERS mechanism for different kinds of materials and SERS-based applications.

Impacts of high-quality coal mine drainage recycling for replenishment of aquatic ecosystems in arid regions of China: Bacterial community responses.

Coal mine water is usually recycled as supplementary water for aquatic ecosystems in arid and semiarid mining regions of China. To ensure ecosystem health, the coal mine water is rigorously treated using several processes, including reverse osmosis, to meet surface water quality standards. However, the potential environmental impacts of this management pattern on the ecological function of receiving water bodies are unclear. In this study, we built several microcosm water ecosystems to simulate the receiving water bodies. High-quality treated coal mine drainage was mixed into the model water bodies at different concentrations, and the sediment bacterial community response and functional changes were systematically investigated. The results showed that the high-quality coal mine drainage could still shape bacterial taxonomic diversity, community composition and structure, with a concentration threshold of approximately 50%. Moreover, both the Mantel test and the structural equation model indicated that the salinity fluctuation caused by the receiving of coal mine drainage was the primary factor shaping the bacterial communities. 10 core taxa in the molecular ecological network influenced by coal mine drainage were identified, with the most critical taxa being patescibacteria and g_Geothermobacter. Furthermore, the pathway of carbohydrate metabolism as well as signaling molecules and interactions was up-regulated, whereas amino acid metabolism showed the opposite trend. All results suggested that the complex physical-chemical and biochemical processes in water ecosystems may be affected by the coal mine drainage. The bacterial community response and underlying functional changes may accelerate internal nutrient cycling, which may have a potential impact on algal bloom outbreaks.

Block-based teaching method based on cybernetics: a trial with 115 Chinese undergraduate medical students.

BACKGROUND: Class attendance is important for academic performance. Personal interactions between teachers and students are difficult in large classes; the number of medical undergraduate students in China ranges from dozens to over 100. It is important for teachers to control the teaching process to improve student attendance and participation. METHODS: Two classes of fourth-year undergraduate medical students, with each class comprising 115 students, participated in the study. One class, the trial group, was taught by the block-based teaching method based on cybernetics. This study was conducted with three of the courses in the Introduction to Oncology subject, and the trial group's courses included several blocks. Each block had a test paper that the students responded to immediately in class using the Internet. The teacher obtained feedback from the students when the rate of correct responses to block-test questions was less than 90%. The teacher adjusted the teaching in the following blocks according to the feedback information. The other class, the control group, was taught using the traditional lecture-based teaching method. RESULTS: The average attendance in the trial group was 104/115 (90.43%), and that in the control group was 83/115 (72.17%) (p = 0.0003). The teacher adjusted the teaching three times in the radiotherapy course owing to the complex ideas. After feedback, information on chemotherapy for the upper body was adjusted once, as was that on chemotherapy for the lower body, owing to students' attitudes. The average total score of the trial group was 86.06 ± 17.46 and that of the control group was 80.38 ± 6.97 (p = 0.041). Questionnaire I showed that the trial group students' attendance and participation were better than in the control group. Questionnaire II showed that the block-based teaching method based on cybernetics was approved by the students. CONCLUSIONS: The block-based teaching method based on cybernetics used in medical classes with large numbers of Chinese undergraduate students had positive effects.

Effects of acid, acid-ZVI/PMS, Fe(II)/PMS and ZVI/PMS conditioning on the wastewater activated sludge (WAS) dewaterability and extracellular polymeric substances (EPS).

The effects of four conditioning approaches: Acid, Acid-zero-valent iron (ZVI)/peroxydisulfate (PMS), Fe(II)/PMS and ZVI/PMS, on wastewater activated sludge (WAS) dewatering and organics distribution in supernatant and extracellular polymeric substances (EPS) layers were investigated. The highest reduction in bound water and the most WAS destruction was achieved by Acid-ZVI/PMS, and the optimum conditions were pH 3, ZVI dosage 0.15 g/g dry solid (DS), oxone dosage 0.07 g/g DS and reaction time 10.6 min with the reductions in capillary suction time (CST) and water content (Wc) as 19.67% and 8.49%, respectively. Four conditioning approaches could result in TOC increase in EPS layers and supernatant, and protein (PN) content in tightly bound EPS (TB-EPS). After conditioning, organics in EPS layers could migrate to supernatant. Polysaccharide (PS) was easier to migrate to supernatant than PN. In addition, Acid, Acid-ZVI/PMS or Fe(II)/PMS conditioning promoted the release of some polysaccharides containing ring vibrations v PO, v C-O-C, v C-O-P functional groups from TB-EPS. ESR spectra proved that both radicals of SO4-· and ·OH contributed to dewatering and organics transformation and migration. CST value of WAS positively correlated with the ratios of PN/PS in LB-EPS and total EPS, while it negatively correlated with TOC, PN content and PS content in TB-EPS, as well as PS content in supernatant and LB-EPS. BWC negatively correlated to zeta potential and TOC value, PN content, and HA content in supernatant.

New model for explaining the over-response phenomenon in percentage of depth dose curve measured using inorganic scintillating materials for optical fiber radiation sensors.

Inorganic scintillating material used in optical fibre sensors (OFS) when used as dosimeters for measuring percentage depth dose (PDD) characteristics have exhibited significant differences when compared to those measured using an ionization chamber (IC), which is the clinical gold standard for quality assurance (QA) assessments. The percentage difference between the two measurements is as high as 16.5% for a 10 × 10 cm2 field at 10 cm depth below the surface. Two reasons have been suggested for this: the presence of an energy effect and Cerenkov radiation. These two factors are analysed in detail and evaluated quantitatively. It is established that the influence of the energy effect is only a maximum of 2.5% difference for a beam size 10 × 10 cm2 compared with the measured ionization chamber values. And the influence of the Cerenkov radiation is less than 0.14% in an inorganic scintillating material in the case of OFS when using Gd2O2S:Tb as the luminescent material. Therefore, there must be other mechanisms leading to over-response. The luminescence mechanism of inorganic scintillating material is theoretically analysed and a new model is proposed and validated that helps explain the over-response phenomenon.

A Framework for an Intelligent and Personalized Fire Evacuation Management System.

Many research studies have focused on fire evacuation planning. However, because of the uncertainties in fire development, there is no perfect solution. This research proposes a fire evacuation management framework which takes advantage of an information-rich building information modeling (BIM) model and a Bluetooth low energy (BLE)-based indoor real-time location system (RTLS) to dynamically push personalized evacuation route recommendations and turn-by-turn guidance to the smartphone of a building occupant. The risk score (RS) for each possible route is evaluated as a weighted summation of risk level index values of all risk factors for all segments along the route, and the route with the lowest RS is recommended to the evacuee. The system will automatically re-evaluate all routes every 2 s based on the most updated information, and the evacuee will be notified if a new and safer route becomes available. A case study with two testing scenarios was conducted for a commercial office building in Tianjin, China, in order to verify this framework.

Valosin-containing protein (VCP) promotes the growth, invasion, and metastasis of colorectal cancer through activation of STAT3 signaling.

Valosin-containing protein (VCP) was previously shown to exhibit high expression in colorectal cancer (CRC) tissues as compared with that in normal tissues; however, the role of VCP in human CRC cells has remained to be elucidated. Two colorectal cancer cell lines HCT116 and RKO were used in the experiment. We introduced lentiviral constructs expressing VCP to infect RKO cells and lenti-shRNA targeting VCP into HCT116 cells, respectively. Cell proliferation, invasion, apoptosis, and cell cycle arrest were subsequently examined by MTT assay, transwell chamber assay, flow cytometry, and western blot analysis, respectively. Furthermore, a subcutaneous tumor mouse model and lung metastasis model was used to investigate the effects of VCP on the growth and metastasis of CRC cells in vivo. VCP knockdown was shown to inhibit cell proliferation, chemoresistance and invasion, and induce apoptosis in the HCT116 CRC cells, whereas VCP over-expression suppressed apoptosis and chemoresponse, promoted proliferation and invasion of the RKO CRC cells. In addition, in the subcutaneous tumor and lung metastasis mouse model, VCP knockdown in HCT116 cells suppressed carcinogenesis and metastasis in vivo. The findings of the present study indicated that VCP is very important for the proliferation and metastasis of CRC; therefore, targeting VCP and its downstream targets may represent novel therapies for the treatment of CRC.

Rethinking the relationships between gel like structure and sludge dewaterability based on a binary gel like structure model: Implications for the online sensing of dewaterability.

The digital transformation of sludge treatment processes requires online sensing of dewaterability. This topic has been attempted for many years based on macroscopic shear rheology. However, the relationship between rheological behavior and dewaterability remains noncommittal, and the reason is unclear. Herein, a binary gel-like structure model was proposed including the interactions network at the supra-flocs level and the gel-like structure at the flocs level. Multiple advanced techniques including optical tweezers were employed to precisely understand the binary gel-like structure and to classify the correlation mechanism between this gel-like structure, rheological behavior, and dewaterability. The analysis of sludge from eight wastewater treatment plants showed the binary gel-like structures at both supra-flocs and flocs levels have significant relationships with sludge dewaterability (p < 0.05). Further deconstruction of the sludge viscoelastic behavior illustrated that the gel-like structure at the supra-flocs level dominates the rheological behavior of sludge. Moreover, the direct description of the binary gel-like structure in four typical sludge treatment processes highlighted the importance of the flocs level's structure in determining the dewaterability. Overall, this study revealed that shear rheology may prefer to stress the interactions network at the supra-flocs level but mask the flocs level's structure, although the latter is important. This observation may provide a general guideline for the design of robust sensors for dewaterability.

Noninvasive Stereotactic Radiotherapy for PADN in an Acute Canine Model of Pulmonary Arterial Hypertension.

This study assesses the feasibility, safety, and effectiveness of noninvasive stereotactic body radiotherapy (SBRT) as an approach for pulmonary artery denervation in canine models. SBRT with CyberKnife resulted in reduced mean pulmonary artery pressure, pulmonary capillary wedge pressure, and pulmonary vascular resistance, and insignificantly increased cardiac output. In comparison to the control group, serum norepinephrine levels at 1 month and 6 months were significantly lower in the CyberKnife group. Computed tomography, pulmonary angiography, and histology analysis revealed that SBRT was associated with minimal collateral damage.

Free nitrous acid-assisted asymmetrical alternating current electrochemistry (FNA-AACE) for multi-heavy metals decontamination in waste activated sludge.

Heavy metal contamination of waste activated sludge (WAS) is a key factor limiting the land application of sludge for nutrients recovery. This study proposes a novel free nitrous acid (FNA)-assisted asymmetrical alternating current electrochemistry (FNA-AACE) process to achieve high-efficiency decontamination of multi-heavy metals (Cd, Pb, and Fe) in WAS. The optimal operating conditions, the heavy metal removal performance of FNA-AACE, and the related mechanisms for maintaining the high performance were systematically investigated. During the FNA-AACE process, FNA treatment was optimal with an exposure time of 13 h at a pH of 2.9 and an FNA concentration of 0.6 mg/g TSS. Then the sludge was washed with EDTA in a recirculating leaching system under asymmetrical alternating current electrochemistry (AACE). The 6-h working and the following electrode cleaning were defined as a working circle of AACE. After three cycles of working-cleaning periods in AACE treatment, the cumulative removal efficiency of the toxic metals Cd and Pb reached over 97% and 93%, respectively, whilst that of Fe was greater than 65%. This surpasses most previously reported efficiencies and possesses a shorter treatment duration and sustainable EDTA circulation. The mechanism analysis suggested that FNA pretreatment provoked the migration of heavy metals for leaching enhancement, as well as reduced the demand for EDTA eluent concentration and increased conductivity, which can improve the AACE efficiency. Meanwhile, the AACE process absorbed the anionic chelates of heavy metals and reduced them to zero-valent particles on the electrode, regenerating the EDTA eluent and maintaining its high extraction efficiency for heavy metals. In addition, FNA-AACE could provide different electric field operation modes, allowing it to have flexibility for the real application processes. This proposed process is expected to be coupled with anaerobic digestion in wastewater treatment plants (WWTPs) for high efficiency of heavy metal decontamination, sludge reduction, and resource/energy recovery.

A comprehensive assessment on sludge conditioning by pyrite acid eluent-activated peroxymonosulfate based on dewaterability, heavy metals risk and ore recovery.

Wastewater activated sludge (WAS) has poor dewaterability and contains heavy metals (HMs), limiting its land application. Therefore, in this study, a novel pyrite acid eluent-activated peroxymonosulfate (Fe2+pyrite/PMS) conditioning approach that can completely recover the residual pyrite and greatly reduce acid use was developed to improve WAS dewaterability, and the HMs chemical speciation and risks of conditioned WAS were assessed. Our results showed that under the optimized operational parameters, the capillary suction time (CST) and water content (Wc) of WAS decreased by 46.03% and 7.75%, respectively. Furthermore, during Fe2+pyrite/PMS conditioning processing, sulfate radical (SO4-) destroyed the extracellular polymeric substances (EPS) matrix, causing bound water release and the decrease of proteins/polysaccharides in outer layered EPS, even the decomposition of some protein-N in tightly bound EPS (TB-EPS) into inorganic-N. In addition, although the total concentration of HMs in the conditioned WAS matrix increased, the Ni concentration decreased in the solid fraction. Further, the risk assessment code (RAC) levels did not increase, and the eco-toxicity of Cr became weakened after Fe2+pyrite/PMS conditioning. However, after acid extraction, the pyrite residue had worsened recycle performance because the passivation layer contained S0/Sn2- on its surface, and no additional elements were detected in the pyrite residue, which had almost no effect on its further usage.

Adsorption-electrochemical mediated precipitation for phosphorus recovery from sludge filter wastewater with a lanthanum-modified cellulose sponge filter.

In this study, the sludge filter wastewater is confirmed to investigate the effects of adsorption-electrochemical mediated precipitation (EMP) driven phosphorus recovery on the basis of lanthanum-modified cellulose sponge filter (LCLM) material. The adsorption-EMP method relies on in situ recovery phosphate (P) from the used desorption agent (NaOH-NaCl binary solution) via the formation of Ca5(PO4)3OH all while preserving the alkalinity of the desorption agents which benefited long-term application. The lanthanum content of LCLM was 9.0 mg/g, and the adsorption capacity reached 226.1 ± 15.2 mg P/g La at an equilibrium concentration of 3.9 mg P/L. After adsorption, 55.7 % of P was recovered, and the corresponding alkalinity increased from 1.9 mmol/L to 2.2 mmol/L. Adsorption mechanism analysis revealed that the high lanthanum usage of LCLM was attributed to the synergistic effect of the lattice oxygen of LaO and LaPO4·0.5H2O crystallite formation. Additionally, the Ca5(PO4)3OH was found precipitated in the precipitation in the cathode chamber (P-CC) rather than on the surface/section of cation exchange membrane (CEM) and cathode indicating that the P recovery process was controlled by the saturation of CaP species in the EMP system and the electromigration effect. These findings present a new strategy to promote the effective utilization of rare earth elements for P adsorption and demonstrate the potential application of adsorption-EMP systems in dephosphorization for wastewater treatment.

Ultrasensitive dual-enhanced sandwich strategy for simultaneous detection of Escherichia coli and Staphylococcus aureus based on optimized aptamers-functionalized magnetic capture probes and graphene oxide-Au nanostars SERS tags.

In this work, a novel surface-enhanced Raman scattering (SERS) sandwich strategy biosensing platform has been established for simultaneously detecting Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Fe3O4@SiO2-Au nanocomposites (NCs) with varying amounts of Au nanocrystals were prepared, and the effect of interparticle gaps on SERS activity was studied by finite-difference time-domain (FDTD) method. The optimal magnetic SERS-active substrates (FS-A5) were functionalized with the specific aptamers to act as capture probes. Meanwhile, graphene oxide-Au nanostars (GO-Au NSs) decorated with Raman reporters and aptamers were used as SERS tags. The loading density of Au NSs on GO was tuned to change the number of SERS active sites. In this proposal, E. coli and S. aureus were first captured by capture probes and then bound with SERS tags to form a sandwich-like structure, which caused enhanced electromagnetic field because of the dual enhancement strategy. Under optimal conditions, SERS platform could detect E. coli and S. aureus simultaneously, and the detection limit was as low as 10 cfu/mL. Our sandwich assay-based dual-enhanced SERS platform provides a new idea for simultaneously detecting multiple pathogens with high selectivity and sensitivity, and thus will have more hopeful prospects in the field of food safety.

Multi-dimensional plasmonic coupling system for efficient enrichment and ultrasensitive label-free SERS detection of bilirubin based on graphene oxide-Au nanostars and Au@Ag nanoparticles.

Rapid and sensitive detection of free bilirubin (BR) is essential for early diagnosis of jaundice and other hepatobiliary diseases. Inspired by sandwich immunoassay strategy, a multi-dimensional plasmonic coupling SERS platform composed of graphene oxide-Au nanostars nanocomposites (GANS NCs) and Au@Ag nanoparticles (NPs) was designed for label-free detection of BR. Specifically, GANS NCs were first prepared, and their excellent SERS activity was ascribed to synergistic enhancement effect of electromagnetic enhancement and chemical enhancement. Furthermore, SERS spectroscopy was used to monitor the adsorption process of BR. Subsequently, secondary reinforcing Au@Ag NPs were directly added, ultimately resulting in a multi-dimensional plasmonic coupling effect. The SERS enhancing mechanism of coupled system was discussed through electromagnetic field simulations. Interestingly, the high-density hotspots generated by strong plasmonic coupling in GANS-Au@Ag substrate could lead to more extraordinary SERS enhancing behavior compared to GANS NCs. Sensing efficiency of the SERS platform was examined by BR with a detection limit down to 10-11 M. Besides, GANS-Au@Ag NCs performed high uniformity and reproducibility. This work not only opens up a new avenue for construction of multi-dimensional plasmonic coupling system, but also offers a new biosensing technology for label-free diagnosis of BR-related diseases, thereby expecting to be applied in clinical diagnosis.

Comparative analysis of tumor markers and evaluation of their predictive value in patients with colorectal cancer.

BACKGROUND: We evaluated the feasibility of CEA/CK20 mRNA and CEA/CA19-9 proteins as tumor markers for colorectal cancer by detecting tumor-specific mRNAs in circulating tumor cells and secreted tumor-specific proteins in the peripheral blood of colorectal cancer patients. PATIENTS AND METHODS: Peripheral blood was obtained from 23 healthy volunteers and 46 colorectal cancer patients on the day of initiation of adjuvant chemotherapy after surgery (stages I-III, n = 27) or on the first day of chemotherapy after diagnosis (stage IV, n = 19). Levels of CEA/CK20 mRNA in peripheral blood mononuclear cells (PBMCs) were determined with quantitative real-time reverse transcription polymerase chain reaction, and serum CEA/CA19-9 protein levels were determined by radioimmunoassay. RESULTS: The detection sensitivity of CK20 mRNA was approximately 1 tumor cell in 1 × 10(7) PBMCs, and that of CEA mRNA was approximately 1 tumor cell in 1 × 10(6) PBMCs. Patients with stage IV colorectal cancer had higher levels of CEA mRNA, CK20 mRNA, and serum CEA than patients at stages I-III. Peripheral blood CEA mRNA levels were predictive of overall survival, while serum protein levels of CEA and CA19-9 had no predictive value. CONCLUSION: Peripheral blood CEA mRNA is a useful marker of overall survival in colorectal cancer patients, that is sensitive and specific.

Vertically co-distributed vanadium and microplastics drive distinct microbial community composition and assembly in soil.

Vanadium (V) and microplastics in soils draw increasing attention considering their significant threats to ecosystems. However, little is known about the vertical co-distribution of V and microplastics in soil profile and their combined effects on microbial community dynamics and assembly. This study investigated the spatial distribution of V and microplastics in the soils at a V smelting site and the associated microbial community characteristics along the vertical gradient. Both V and microplastics were found in the 50 cm soil profile with average concentrations of 203.5 ± 314.4 mg/kg and 165.1 ± 124.8 item/kg, respectively. Topsoil (0-20 cm) and subsoil (20-50 cm) displayed distinct microbial community compositions. Metal-tolerant (e.g., Spirochaeta, Rubellimicrobium) and organic-degrading (e.g., Bradyrhizobium, Pseudolabrys) taxa as biomarkers were more abundant in the topsoil layer. V and microplastics directly affected the microbial structure in the topsoil and had indirect influences in the subsoil, with direct impacts from organic matter. In topsoil, deterministic processes were more prevalent for community assembly, whereas stochastic processes governed the subsoil. The interspecific relationship was closer in topsoil with greater network complexity and higher modularity. These findings promote the understanding of distinct heterogeneity of microbial communities jointly driven by V and microplastics in soil environment.

An electro-peroxone oxidation-Fe(III) coagulation sequential conditioning process for the enhanced waste activated sludge dewatering: Bound water release and organics multivariate change.

As a by-product of wastewater treatment, waste activated sludge (WAS) has complex composition, strong hydrophilic extracellular polymeric substance (EPS), which make it difficult to dewater. In this study, an electro-peroxone oxidation-Fe(III) coagulation (E-peroxone-Fe(III)) sequential conditioning approach was developed to improve WAS dewaterability. At E-peroxone oxidation stage, hydrogen peroxide was generated through 2-electron path on a carbon polytetrafluoroethylene cathode, and reacted with the sparged O3 to produce hydroxyl radicals. At the subsequent coagulation stage, Fe(III) was dosed to coagulate the small WAS fragments and release water from WAS. Along E-peroxone-Fe(III) subsequent conditioning process, the physicochemical properties of WAS, main components, functional groups and evolution of protein secondary structure, and typical amino acids in EPS, as well as the type and semi-quantitative of elements in WAS, were investigated. The results indicated that under the optimal conditions, the reductions of specific resistance to filterability (SRF) and capillary suction time (CST) for WAS equalled 78.18% and 71.06%, respectively, and its bound water content decreased from 8.87 g/g TSS to 7.67 g/g TSS. After E-peroxone oxidation, part of protein and polysaccharide migrated outside from TB-EPS to slime, the ratio of α-helix/(ß-sheet + random coil) declined, even some of organic-N disintegrated to inorganic-N. At Fe(III) coagulation stage, re-coagulation of the dispersed WAS fragments and easy extraction from inner EPS for protein and polysaccharide occurred. Furthermore, the protein secondary structure of ß-sheet increased by 13.48%, the contents of hydrophobic and hydrophilic amino acids also increased. In addition, a strong negative correlation between the hydrophobic amino acid content of Met in slime and CST or SRF (R2CST = -0.999, p < 0.05 or R2SRF = -0.948, p < 0.05) occurred, while a strong positive correlation between the hydrophilic amino acid content of Cys in TB-EPS and CST or SRF (R2CST = 0.992, p < 0.05 or R2SRF = 0.921, p < 0.05) occurred, which could be related to the WAS dewaterability.

Electrical impedance spectroscopy as a potential tool to investigate the structure and size of aggregates during water and wastewater treatment.

Microscopic structure and size are important metrics for estimating aggregates environmental behaviors during water and wastewater treatment. However, in-situ determination of these characteristics is still a challenge. Here, we drew inspiration from a block disassembly process to propose an electrical impedance spectroscopy (EIS) method and constructed a generalized framework to associate macroscale electrical properties with microscopic structure and size-related characteristics of aggregates of different hierarchies. Extracted via EIS, the proposed models were verified to be capable of describing the self-similarity of aggregates and capturing the fractal and size information. Further, the proposed models exhibited a wide range of applications, which agrees well with the data gathered from various activated sludges, other colloids, and microgels in water and wastewater treatment. Finally, the EIS method was achieved online monitoring of fractal dimension and floc size during a sludge pre-oxidation conditioning process, which was elected as an example to illustrate the potential online applications of this EIS method in real water and wastewater environment. The obtained on-line data were used to indicate the potential suitable oxidation time during sludge pre-oxidation conditioning. These observations may inspire new methods of quantifying the aggregate structure and promote intelligent and dynamic decision-making during water and wastewater treatment.