Evaluation of safety, efficacy, and risk factors of different breast reconstruction strategies following polyacrylamide hydrogel removal: A 20-year retrospective cohort study of 436 cases.

BACKGROUND: Globally implemented for breast augmentation, polyacrylamide hydrogel (PAAG) always leads to breast deformity upon its removal. Despite a pressing need for breast reconstruction following PAAG removal to address aesthetic issues, the optimal timing remains controversial. METHODS: A retrospective cohort study analyzed patients who underwent PAAG removal between 2003 and 2023. They were categorized into three cohorts: immediate (IBR), delayed (DBR), or no breast reconstruction (NBR) post-PAAG removal. Complication rates, re-operation frequencies, risk factors, and BREAST-Q scores were assessed. RESULTS: A total of 436 breasts were identified and divided into IBR (n = 126), DBR (n = 48), and NBR (n = 262). Complication rates were 50.0 % (IBR), 31.3 % (DBR), and 26.7 % (NBR) (P < 0.001); reoperation rates were 26.2 % (IBR), 18.8 % (DBR), and 13.0 % (NBR) (P = 0.006). IBR showed significantly shorter complication-free survival than NBR (113.38 ± 8.34 vs. 178.21 ± 6.82 months; log-rank P < 0.001). Cox regression identified injection period, aspiration history, Baker grade II/III/IV, glandular infiltration, and IBR as independent predictors of higher postoperative complications. As for the Breast-Q scores, physical well-being was similar across groups. However, NBR scored significantly lower for postoperative sexual well-being (P < 0.001), psychosocial well-being (P < 0.001), and satisfaction with breasts (P = 0.001) compared to both IBR and DBR. CONCLUSIONS: DBR is a safe and effective solution for secondary breast deformities after PAAG removal. Notably, patients with prolonged injection histories, previous aspiration history, Baker Grade II/III/IV, and MRI evidence of gel infiltration into glandular tissues are at a higher risk for postoperative complications. These findings may be beneficial for optimizing strategies to manage patients with PAAG injections in clinical practice.

Mechanisms of efficient polyacrylamide degradation: From multi-omics analysis to structural characterization of two amidohydrolases.

Polyacrylamide (PAM) is a high molecular weight polymer with extensive applications. However, inefficient natural degradation of PAM results in its environmental accumulation. Here, using multi-omics analysis, we constructed the PAM biodegradation pathway in Klebsiella sp. PCX, an efficient PAM-degrading bacterium. Subsequently, two unclassified amidohydrolases (PCX00451 and PCX04581) were identified as key factors for rapid PAM biodegradation, both of which possessed much higher hydrolysis efficiency for PAM than for small molecule amide compounds. Besides, crystal structures of PCX00451 and PCX04581 were solved. Both two amidohydrolases were consisted with a twisted triosephosphateisomerase (TIM)-barrel and a smaller ß-sandwich domain. And their binding pockets were in the conserved metal center of TIM-barrel domain. Moreover, Asp267 of PCX00451 and Asp282 of PCX04581 were examined as active sites for acid/base catalysis. Our research characterized the molecular mechanisms of two efficient amidohydrolases, providing theoretical basis and valuable tools for PAM bioremediation.

The influence of polyacrylamide gel substrate elasticity on primary cultures of rat retinal ganglion cells.

In vitro primary cell culture models of retinal ganglion cells (RGC) are widely used to study pathomechanisms of diseases such as glaucoma. The biomechanic interaction with the culture substrate is known to influence core cellular functions. RGC cultures, however, are usually grown on rigid plastic or glass substrates. We hypothesized that soft polyacrylamide gel substrates may alter survival and neurite outgrowth of primary cultured RGC. Primary retinal cultures from postnatal (day 1-6) Wistar rats were grown on glass coverslips or polyacrylamide (PA) gel substrate with different Young's elastic moduli (0.75, 10 or 30 kPa). Substrates were coated with Poly-l-lysine and / or laminin. RGC were immunostained with anti-beta-III-tubulin. Total neurite length, growth cone morphology, RGC density, mitochondrial morphology and transport as well as pro-survival pathways (Erk1/2, Akt, CREB) were assessed. PA gel substrates of E = 10 kPa significantly increased the total neurite length by factor 1.5 compared to glass (p = 0.02). The growth cone area was significantly larger by factor 5.3 on 30 kPa gels (p = 0.01). The presence of a substrate coating was more important for neurite outgrowth and RGC survival on PA gels (poly-l-lysine > laminin) than on glass. Neither mitochondrial morphology and motility nor the activation of pro-survival pathways significantly differed between the four substrates. PA gel substrates significantly enhanced RGC neurite outgrowth. The signaling cascades mediating this effect remain to be determined.

TEMPO oxidized cellulose nanofiber-reinforced sodium alginate encapsulated poly(acrylamide) microcapsules and its releasing behaviours for enhancing oil recovery.

Poly(acrylamide) (PAM) has excellent thickening ability as a conventional flooding agent. However, PAM confronts the problems of high injection pressure and high shear loss in the process of oil extraction, which have limited its application in this field. In this work, 2, 2, 6, 6-Tetramethylpiperidinooxy oxidized cellulose nanofibers (TOCNFs) enhanced sodium alginate (SA) shell was used to encapsulate PAM to form microcapsule. The composition, morphology, structure and the releasing behaviours of TOCNFs enhanced microcapsules was tested. Mechanical stirring was used to simulate the state of polymer subjected to shear during stratigraphic transport. The release performance of the microcapsules was characterized by measuring the change of viscosity with time. The ratio of the shell material with the best performance was explored, and the enhancement mechanism of the SA shell by TOCNFs was discussed. The experiments showed that the release time of PAM from the microcapsules was significantly prolonged with the addition of TOCNFs. The longest release time was observed when the ratio of SA and TOCNFs was 5: 1, with the release time of the microcapsules from the original 8 h to 16 h. The enhanced shear resistance of the microcapsules was attributed to the semi-interpenetrating network structure of SA and TOCNFs via Ca2+ cross-linking as well as hydrogen bonding. The prepared microcapsules have promising applications in enhancing oil recovery.

Exploring Electrochemical Direct Writing Machining of Patterned Microstructures on Zr702 with Polyacrylamide Polymer Electrolyte.

Zirconium alloys possess excellent wear resistance, which ensures the durability and longevity of the components, making them widely used in medical and other fields. To enhance the functionality of these materials, it is often necessary to fabricate functional microstructures on their surfaces. Electrochemical machining (ECM) techniques demonstrate excellent machining performance for these metals, particularly in the processing of microstructures on complex curved surfaces. However, ECM often faces challenges due to the fluid nature of the electrolyte, resulting in low machining accuracy and localization. This paper proposes a novel method for fabricating complex patterned microstructures using a maskless electrochemical direct writing technique with a polyacrylamide (PAM) polymer electrolyte. By leveraging the non-Newtonian properties of PAM, this method effectively confines the electrolyte to specific areas, thus addressing the issue of poor localization in traditional ECM and reducing stray corrosion. To elucidate the electrochemical removal mechanism of Zr702 in the presence of PAM, polarization curves, viscosity characteristics, and current efficiency parameters were analyzed. Additionally, an experimental study was conducted using a custom-designed nozzle structure. The results showed that the PAM electrolyte could effectively reduce the EF, positively impacting machining accuracy and localization. By controlling the nozzle's motion trajectory, complex microstructures were successfully fabricated through direct writing, demonstrating promising application prospects.

Harnessing an elastic flow instability to improve the kinetic performance of chromatographic columns.

Despite decades of research and development, the optimal efficiency of slurry-packed HPLC columns is still hindered by inherent long-range flow heterogeneity from the wall to the central bulk region of these columns. Here, we show an example of how this issue can be addressed through the straightforward addition of a semidilute amount (500 ppm) of a large, flexible, synthetic polymer (18 MDa partially hydrolyzed polyacrylamide, HPAM) to the mobile phase (1% NaCl aqueous solution, hereafter referred to as "brine") during operation of a 4.6 mm × 300 mm column packed with 10µm BEHTM 125 Å particles. Addition of the polymer imparts elasticity to the mobile phase, causing the flow in the interparticle pore space to become unstable above a threshold flow rate. We verify the development of this elastic flow instability using pressure drop measurements of the friction factor versus Reynolds number. In prior work, we showed that this flow instability is characterized by large spatiotemporal fluctuations in the pore-scale flow velocities that may promote analyte dispersion across the column. Axial dispersion measurements of the quasi non-retained tracer thiourea confirm this possibility: they reveal that operating above the onset of the instability improves column efficiency by greater than 100%. These experiments thereby suggest that elastic flow instabilities can be harnessed to mitigate the negative impact of trans-column flow heterogeneities on the efficiency of slurry-packed HPLC columns. While this approach has its own inherent limitations and constraints, our results lay the groundwork for future targeted development of polymers that can impart elasticity when dissolved in commonly used liquid chromatography mobile phases, and can thereby generate elastic flow instabilities to help improve the resolution of HPLC columns.

Dialysis treatment, in vitro, and anticoagulation activity of polysulfone-polyacrylamide based-blend membranes: an experimental study.

The majority of treatments are performed with polysulfone (PSf) membranes. The main issue of the PSf membrane is its lack of endothelial function, leading to various processes like platelet adhesion, protein adsorption, and thrombus formation when comes in contact with blood. The crucial aspect in the development of hemodialysis (HD) membrane materials is a biocompatibility factor. This study aims to improve the performance and biocompatibility of PSf membranes by utilizing polyethylene glycol (PEG) as a pore-forming agent and polyacrylamide (PAA) as a multifunctional modifying additive owing to its non-toxic, and biocompatible nature. The formulated HD membranes were characterized using Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), and Water Contact Angle (WCA) measurements. The biocompatibility results showed that PSf-PAA membranes reduced the adsorption of bovine serum albumin (BSA) protein, hemolysis process, thrombus formation, and platelets adhesion with improved in vitro cytotoxicity results as well as anticoagulation performance. The protein separation results showed that PSf-PAA membranes were able to reject 90.1% and 92.8% of BSA protein. The membranes also showed better uremic waste clearance for urea (76.56% and 78.24%) and creatinine (73.71% and 79.13%) solutes, respectively. It is conceivable that these modern-age membranes may surpass conventional HD membranes regarding both efficiency and effectiveness.

Surgical treatment after augmentation mammoplasty with polyacrylamide hydrogel.

Polyacrylamide hydrogel mammoplasty is a simple and relatively affordable surgery. However, this procedure is associated with a significant frequency of late complications, prompting its suspension in 2006. Despite this, patients continue facing long-term consequences. These include hydrogel migration, changes in breast shape and volume, granulomas, fistulas, and abscess formation. The clinical case described here presents the surgical treatment after augmentation mammoplasty with polyacrylamide hydrogel performed 35 years ago.

A time-saving one-step polyacrylamide gel with a colored stacking gel for SDS-PAGE and western blotting.

A time-saving, one-step polyacrylamide gel preparation method enabling simultaneous preparation of separating and stacking gels was previously reported, but the boundary between the separating and stacking gels was often not well defined. As such, determining whether the gel preparation failed is difficult before SDS-PAGE is carried out. To address this issue, a one-step polyacrylamide gel preparation method was developed in which the stacking gel is colored to allow better visualization of the border between the stacking and separating gels. This new one-step method saves time and achieves comparable performance for SDS-PAGE and western blotting to that obtained with conventional gels.

A straightforward cell culture insert model to incorporate biochemical and biophysical stromal properties into transplacental transport studies.

The placental extracellular matrix (ECM) dynamically remodels over pregnancy and in disease. How these changes impact placental barrier function is poorly understood as there are limited in vitro models of the placenta with a modifiable stromal compartment to mechanistically investigate these extracellular factors. We developed a straightforward method to incorporate uniform hydrogels into standard cell culture inserts for transplacental transport studies. Uniform polyacrylamide (PAA) gels were polymerized within cell culture inserts by (re)using the insert packaging to create a closed, controllable environmental chamber. PAA pre-polymer solution was added dropwise via a syringe to the cell culture insert and the atmosphere was purged with an inert gas. Transport and cell culture studies were conducted to validate the model. We successfully incorporated ECM-functionalized uniform PAA gels into cell culture inserts, enabling cell adhesion and monolayer formation. Imaging and analyte transport studies validated gel formation and expected mass transport results, and successful cell studies confirmed cell viability, stiffness-mediated YAP translocation, and that the model could be used in transplacental transport studies. Detailed methods and validation protocols are included. The incorporation of a PAA gel within a cell culture insert enables independent study of placental ECM biophysical and biochemical properties in the context of transplacental transport. These straightforward and low-cost methods to build three-dimensional cellular models are readily adoptable by the wider scientific community.

Effects of pressure on the biogeochemical and geotechnical behavior of treated oil sands tailings in a pit lake scenario.

Reclamation options for oil sands fluid fine tailings (FFT) are limited due to its challenging geotechnical properties, which include high water and clay contents and low shear strength. A feasible reclamation option for tailings with these properties is water capped FFT deposits (pit lakes). A relatively new proposal is to deposit FFT that has been treated with alum and polyacrylamide in pit lakes. Though over 65 Mm3 of alum/polyacrylamide treated FFT has been deposited to date, there is limited publicly available information on the biogeochemical and geotechnical behavior of this treated FFT. Further, the effects of pressure from overlying tailings on microbial activity and biogeochemical cycling in oil sands tailings has not been previously investigated. Twelve 5.5 L columns were designed to mimic alum/polyacrylamide treated FFT deposited beneath a water cap. A 2x2 factorial design was used to apply pressure and hydrocarbon amendments to the tailings. Pressure (0.3-5.1 kPa) was applied incrementally and columns were monitored for 360 d. Pressure significantly enhanced consolidation and microbial activity in treated FFT. Columns with pressure generated significantly more CH4(g) and CO2(g) and had significant increases in dissolved organic carbon and chemical oxygen demand in the FFT and water caps. The enhanced microbial activity in columns with pressure indicates that pressure increased the solubility of microbial substrates and metabolites in the tailings, thereby increasing the bioavailability of these compounds. Ammonium generation was significantly higher in columns with pressure, suggesting that microorganisms utilized polyacrylamide and/or N2 fixation as a nitrogen source to meet enhanced nutrient demands. Pressure also impacted microbial community structure, shifting methanogenic communities from hydrogenotrophic methanogens to predominately acetoclastic methanogens. This study also revealed the importance of sulfur cycling in treated FFT. Extensive sulfate reduction occurred in all columns, generating dissolved sulfides and H2S(g), and this was accelerated by hydrocarbon amendments.

A novel hydrogel composite of chitosan-phytic acid complex with PAAm: Characterization and adsorptive properties for UO22+and methylene blue.

The composite of a polyelectrolyte combination of chitosan and phytic acid (CsPa) and its entrapped form in polyacrylamide (PAAmCsPa) were synthesized. The composites were characterized by a number of methods including ATR-FTIR, SEM-EDX, XRD and XPS. The adsorptive properties of CsPa and PAAmCsPa were analyzed and modelled for UO22+ and methylene blue (MB+). The results showed that the composites exhibited physico-chemical properties that were both inherited from the components as well as unique to them. The isotherms of UO22+ and MB+ were L-type Giles isotherms. The adsorption kinetics followed the pseudo-second-order model, in contrast to the Langmuir model, which predicts first-order kinetics for both species. According to the Weber-Morris model, the nature of the adsorption process was ion exchange and/or complex formation for both composites and ions. The thermodynamics showed that the adsorption process was endothermic (ΔH > 0), with increasing entropy (ΔS > 0) and spontaneous (ΔG < 0). The reusability tests of the composites for UO22+ adsorption showed that the composites were substantially reusable for 6 cycles. The composites were selective for UO22+ over MB+ ions, and UO22+ adsorption increased significantly when MB+ adsorbed composites were used. Reproducible measurements demonstrating the storability of the composites were obtained over a period of approximately one year.

Clinical Experience in the Management of the Polyacrylamide Hydrogel (PAAG) Associated Complications Including Four Breast Cancer Cases: A Retrospective Study of 135 Cases.

BACKGROUND: Complications often arose after polyacrylamide hydrogel (PAAG) injections for breast augmentation. This study aimed to explore the complications and clinical management of breast augmentation with PAAG. METHODS: We retrospectively analyzed the data of 135 patients who underwent breast PAAG removal from January 2011 to December 2023 in our hospital. We also comprehensively analyzed the postoperative clinical results, subsequent complications, and clinical management after PAAG injections. RESULTS: Induration and nodules (60.0%), pain (27.4%), anxiety (22.2%), migration (13.3%), asymmetry (8.1%), swelling (5.9%), infection (5.2%), calcification (3.7%), and breast cancer (BC) (3.0%) were a few complications after PAAG injections. Although breast cancer was a rare complication, it might be covered up by PAAG tissue. Eighty-eight patients had undergone PAAG removal, while 47 patients had additional breast reconstruction surgery. The post-surgical complications included PAAG residue (17.0%), skin laxity (7.4%), hemorrhage (2.2%), reoperation (1.5%), and nipple or breast asymmetry (1.5%). Additionally, the BREAST-Q scores revealed that patients with breast reconstruction had a significant better outcomes in psychosocial well-being (p < 0.001), satisfaction with breasts (p < 0.001), and sexual well-being (p = 0.008). CONCLUSION: Multiple complications could occur after PAAG injections for breast augmentation. Although rare, BC might need more clinical attention. PAAG removal could alleviate some complications, and breast reconstruction contributed to improved patient satisfaction, psychosocial well-being, and sexual well-being. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Integrating machine learning for the optimization of polyacrylamide/alginate hydrogel.

Hydrogels are highly promising due to their soft texture and excellent biocompatibility. However, the designation and optimization of hydrogels involve numerous experimental parameters, posing challenges in achieving rapid optimization through conventional experimental methods. In this study, we leverage machine learning algorithms to optimize a dual-network hydrogel based on a blend of acrylamide (AM) and alginate, targeting applications in flexible electronics. By treating the concentrations of components as experimental parameters and utilizing five material properties as evaluation criteria, we conduct a comprehensive property assessment of the material using a linear weighting method. Subsequently, we design a series of experimental plans using the Bayesian optimization algorithm and validate them experimentally. Through iterative refinement, we optimize the experimental parameters, resulting in a hydrogel with superior overall properties, including heightened strain sensitivity and flexibility. Leveraging the available experimental data, we employ a classification algorithm to separate the cutoff data. The feature importance identified by the classification model highlights the pronounced impact of AM, ammonium persulfate, and N,N-methylene on the classification outcomes. Additionally, we develop a regression model and demonstrate its utility in predicting and analyzing the relationship between experimental parameters and hydrogel properties through experimental validation.

Tailoring surface stiffness to modulate senescent macrophage immunomodulation: Implications for osteo-/angio-genesis in aged bone regeneration.

The application of biomaterials in bone regeneration is a prevalent clinical practice. However, its efficacy in elderly patients remains suboptimal, necessitating further advancements. While biomaterial properties are known to orchestrate macrophage (MΦ) polarization and local immune responses, the role of biomaterial cues, specifically stiffness, in directing the senescent macrophage (S-MΦ) is still poorly understood. This study aimed to elucidate the role of substrate stiffness in modulating the immunomodulatory properties of S-MΦ and their role in osteo-immunomodulation. Our results demonstrated that employing collagen-coated polyacrylamide hydrogels with varying stiffness values (18, 76, and 295 kPa) as model materials, the high-stiffness hydrogel (295 kPa) steered S-MΦs towards a pro-inflammatory M1 phenotype, while hydrogels with lower stiffness (18 and 76 kPa) promoted an anti-inflammatory M2 phenotype. The immune microenvironment created by S-MΦs promoted the bioactivities of senescent endothelial cells (S-ECs) and senescent bone marrow mesenchymal stem cells BMSCs (S-BMSCs). Furthermore, the M2 S-MΦs, particularly incubated on the 76 kPa hydrogel matrices, significantly enhanced the ability of angiogenesis of S-ECs and osteogenic differentiation of S-BMSCs, which are crucial and interrelated processes in bone healing. This modulation aided in reducing the accumulation of reactive oxygen species in S-ECs and S-BMSCs, thereby significantly contributing to the repair and regeneration of aged bone tissue.

An algae-based polymer material as a pesticide adjuvant for mitigating off-target drift.

Off-target pesticide drift from cropland is a major source of pesticide exposure to pollinating insects inhabiting crop and wildlands in the lower Mississippi Delta (LMD) in the USA. This study is aimed to develop a drift-reducing pesticide adjuvant that is less/nontoxic to honeybees. Ongoing toxicology experiments with two widely-used insecticides and sodium alginate (SA) pointed out reductions in honeybee mortality compared to an industry standard reference polyacrylamide (PAM). When used as an adjuvant to spray the same insecticides described above, SA did not interfere in killing the target pests. Therefore, SA has been tested as a drift-reducing pesticide adjuvant to protect honeybees. Spray experiments in the lab were carried out in four sets: (i) water only, (ii) water and adjuvant, (iii) water and pesticide, and (iv) water, pesticide and adjuvant. Each set contained 18 treatment combinations to cover the ranges in spray pressure (three), adjuvant dose (three), and spray nozzles (two). The droplet spectrum was analyzed using a P15 image analyzer. Diameters of 10 %, 50 % and 90 % volumes (DV10, DV50, and DV90), droplet velocity, standard deviation and relative span were measured. The drift reduction potential (DRP) of SA was analyzed by (i) dose, (ii) spray pressure, and (iii) nozzle type. The DRP of SA is compared to that of PAM. Additionally, three field experiments were carried out to analyze the efficiency of SA in reducing pesticide drift. The results from our experiments collectively indicate that SA has significant potential in mitigating drift as well as minimizing pesticide toxicity to honeybees.

Structural and Mechanistic Insights into a Novel Monooxygenase for Poly(acrylic acid) Biodegradation.

Polyacrylamide (PAM) is a high-molecular-weight polymer with extensive applications. However, the inefficient natural degradation of PAM results in environmental accumulation of the polymer. Biodegradation is an environmentally friendly approach in the field of PAM treatment. The first phase of PAM biodegradation is the deamination of PAM, forming the product poly(acrylic acid) (PAA). The second phase of PAM biodegradation involves the cleavage of PAA into small molecules, which is a crucial step in the degradation pathway of PAM. However, the enzyme that catalyzes the degradation of PAA and the molecular mechanism remain unclear. Here, a novel monooxygenase PCX02514 is identified as the key enzyme for PAA degradation. Through biochemical experiments, the monooxygenase PCX02514 oxidizes PAA with the participation of NADPH, causing the cleavage of carbon chains and a decrease in the molecular weight of PAA. In addition, the crystal structure of the monooxygenase PCX02514 is solved at a resolution of 1.97 Å. The active pocket is in a long cavity that extends from the C-terminus of the TIM barrel to the protein surface and exhibits positive electrostatic potential, thereby causing the migration of oxygen-negative ions into the active pocket and facilitating the reaction between the substrates and monooxygenase PCX02514. Moreover, Arg10-Arg125-Ser186-Arg187-His253 are proposed as potential active sites in monooxygenase PCX02514. Our research characterizes the molecular mechanism of this monooxygenase, providing a theoretical basis and valuable tools for PAM bioremediation.

Comparative study on the effects of anionic, cationic, and nonionic polyacrylamide surface modified magnetic micro-particles (MMP) for anaerobic digestion treatment of vegetable waste water (VWW).

Anaerobic digestion provides a solution for the treatment of vegetable waste water (VWW), but there are currently limited targeted treatment methods available. Building upon previous studies, this research investigated the effects of polyacrylamide-modified magnetic micro-particles (MMP) on anaerobic digestion (AD) of VWW. Three variations of these particles were created by grafting anionic, cationic, and non-ionic polyacrylamide (PAM) onto the MMPs' surfaces, resulting in aPAM-MMP, cPAM-MMP, and nPAM-MMP, respectively. In AD experiments, the addition of aPAM-MMP notably enhanced the degradation of chemical oxygen demand (COD) in VWW. COD decreased to 1290 mg/L in the reactor with aPAM-MMP by day 12 and remained low, while the other reactors had COD concentrations of 4137.5, 5510, and 3010 mg/L on the same day, decreasing thereafter. This modification also improved the production and utilization of hydrogen gas and volatile fatty acids (VFAs), along with the conversion of methane. When tested for bioaffinity using fluorescent GFP-E.coli bacteria, the aPAM-MMP, cPAM-MMP, and nPAM-MMP demonstrated increases in fluorescence intensity by 51.66%, 36.13%, and 37.02%, respectively, compared to unmodified MMP when attached with GFP-E.coli. Further analyses of microbial community revealed that the reactor with aPAM-MMP had the highest microbial richness and enriched bacteria capable of organic matter degradation, such as Bacteroidota, Synergistota, Chloroflexi, Halobacterota phyla, and Parabacteroides, Muribaculaceae, and Azotobacter genera. In conclusion, our experiment verifies that APAM-MMP promotes anaerobic treatment of VWW and provides a novel reference point for enhancing VWW degradation.

Heterogeneous electro-Fenton removal of polyacrylamide in aqueous solution over CoFe2O4 catalyst.

Polyacrylamide (PAM) in environmental water has become a major problem in water pollution management due to its high molecular mass, high viscosity and non-absorption by soil. CoFe2O4 with strong magnetic properties was prepared by solvent-thermal synthesis method and used as the catalyst for the removal on PAM in heterogeneous Electro-Fenton (EF) system. It showed that the removal efficiency of PAM by the heterogeneous EF system using CoFe2O4 catalyst was 92.01% at pH 3 after 120 min. Further studies indicated that ·OH was the most significant active species for the removal of PAM, and the contribution of ·O2- and SO4·- for the removal of PAM was less than 15%. The reusability test and XRD, XPS, FTIR analyses proved that the catalyst had good stability. After a repeated use for five times, the catalyst still had a high PAM removal rate and stable structure. The valence distribution and functional groups of the phase components of the catalyst did not change significantly before and after the reaction. The possible mechanism of catalyst activation of H2O2 was deduced by mechanism investigation. The CoFe2O4 is an efficient and promising catalyst for the removal of PAM wastewater.

Suppression of Zinc Dendrite Growth by Enhanced Polyacrylamide Gel Electrolytes in Zinc-ion Battery.

Aqueous zinc-ion batteries have become a promising energy storage battery due to high theoretical specific capacity, abundant zinc resources and low cost. However, zinc dendrite growth and hydrogen evolution reaction limit their application. This study aims to improve the cycling performance and stability of aqueous zinc-ion batteries by improving the gel electrolyte. Polyacrylamide (PAM) is selected as the base material of the gel electrolyte, which has good stability and safety, but the water retention capacity, Zn2+ migration number, and ionic conductivity of PAM are low, which affects the long-term stability of the battery. In response to these problems, we optimized PAM by chemical cross-linking method, and formed an enhanced PAM gel by adding disodium citrate dihydrate (SC). Experimental results show that the introduction of an appropriate amount of SC in the enhanced PAM gel electrolyte can significantly improve its electrochemical performance. The zinc-ion symmetric battery achieved a stable cycle of more than 2100 hours at a current density of 0.5 mA cm-2, which is mainly attributed to the inhibitory effect of the enhanced PAM gel on zinc dendrite growth and hydrogen evolution reaction. This study provides a new direction for the development and application of flexible zinc-ion batteries.