Global pattern and determinant for interaction of seasonal influenza viruses.

BACKGROUND: The prevalence of different types/subtypes varies across seasons and countries for seasonal influenza viruses, indicating underlying interactions between types/subtypes. The global interaction patterns and determinants for seasonal influenza types/subtypes need to be explored. METHODS: Influenza epidemiological surveillance data, as well as multidimensional data that include population-related, environment-related, and virus-related factors from 55 countries worldwide were used to explore type/subtype interactions based on Spearman correlation coefficient. The machine learning method Extreme Gradient Boosting (XGBoost) and interpretable framework SHapley Additive exPlanation (SHAP) were utilized to quantify contributing factors and their effects on interactions among influenza types/subtypes. Additionally, causal relationships between types/subtypes were also explored based on Convergent Cross-mapping (CCM). RESULTS: A consistent globally negative correlation exists between influenza A/H3N2 and A/H1N1. Meanwhile, interactions between influenza A (A/H3N2, A/H1N1) and B show significant differences across countries, primarily influenced by population-related factors. Influenza A has a stronger driving force than influenza B, and A/H3N2 has a stronger driving force than A/H1N1. CONCLUSION: The research elucidated the globally complex and heterogeneous interaction patterns among influenza type/subtypes, identifying key factors shaping their interactions. This sheds light on better seasonal influenza prediction and model construction, informing targeted prevention strategies and ultimately reducing the global burden of seasonal influenza.

Characterizing the antigenic evolution of pandemic influenza A (H1N1) pdm09 from 2009 to 2023.

The H1N1pdm09 virus has been a persistent threat to public health since the 2009 pandemic. Particularly, since the relaxation of COVID-19 pandemic mitigation measures, the influenza virus and SARS-CoV-2 have been concurrently prevalent worldwide. To determine the antigenic evolution pattern of H1N1pdm09 and develop preventive countermeasures, we collected influenza sequence data and immunological data to establish a new antigenic evolution analysis framework. A machine learning model (XGBoost, accuracy = 0.86, area under the receiver operating characteristic curve = 0.89) was constructed using epitopes, physicochemical properties, receptor binding sites, and glycosylation sites as features to predict the antigenic similarity relationships between influenza strains. An antigenic correlation network was constructed, and the Markov clustering algorithm was used to identify antigenic clusters. Subsequently, the antigenic evolution pattern of H1N1pdm09 was analyzed at the global and regional scales across three continents. We found that H1N1pdm09 evolved into around five antigenic clusters between 2009 and 2023 and that their antigenic evolution trajectories were characterized by cocirculation of multiple clusters, low-level persistence of former dominant clusters, and local heterogeneity of cluster circulations. Furthermore, compared with the seasonal H1N1 virus, the potential cluster-transition determining sites of H1N1pdm09 were restricted to epitopes Sa and Sb. This study demonstrated the effectiveness of machine learning methods for characterizing antigenic evolution of viruses, developed a specific model to rapidly identify H1N1pdm09 antigenic variants, and elucidated their evolutionary patterns. Our findings may provide valuable support for the implementation of effective surveillance strategies and targeted prevention efforts to mitigate the impact of H1N1pdm09.

Biofabrication of engineered blood vessels for biomedical applications.

To successfully engineer large-sized tissues, establishing vascular structures is essential for providing oxygen, nutrients, growth factors and cells to prevent necrosis at the core of the tissue. The diameter scale of the biofabricated vasculatures should range from 100 to 1,000 µm to support the mm-size tissue while being controllably aligned and spaced within the diffusion limit of oxygen. In this review, insights regarding biofabrication considerations and techniques for engineered blood vessels will be presented. Initially, polymers of natural and synthetic origins can be selected, modified, and combined with each other to support maturation of vascular tissue while also being biocompatible. After they are shaped into scaffold structures by different fabrication techniques, surface properties such as physical topography, stiffness, and surface chemistry play a major role in the endothelialization process after transplantation. Furthermore, biological cues such as growth factors (GFs) and endothelial cells (ECs) can be incorporated into the fabricated structures. As variously reported, fabrication techniques, especially 3D printing by extrusion and 3D printing by photopolymerization, allow the construction of vessels at a high resolution with diameters in the desired range. Strategies to fabricate of stable tubular structures with defined channels will also be discussed. This paper provides an overview of the many advances in blood vessel engineering and combinations of different fabrication techniques up to the present time.

This review covers several aspects and advancements of engineered blood vessel biofabrication, which are essential for establishment of large-sized tissues in different areas of biomedical applications.

Quenching residual H2O2 from UV/H2O2 with granular activated carbon: A significant impact of bicarbonate.

UV/H2O2 has been used as an advanced oxidation process to remove organic micropollutants from drinking water. It is essential to quench residual H2O2 to prevent increased chlorine demand during chlorination/chloramination and within distribution systems. Granular activated carbon (GAC) filter can quench the residual oxidant and eliminate some of the dissolved organic matter. However, knowledge on the kinetics and governing factors of GAC quenching of residual H2O2 from UV/H2O2 and the mechanism underlying the enhancement of the process by HCO3- is limited. Therefore, this study aimed to analyse the kinetics and influential factors, particularly the significant impact of bicarbonate (HCO3-). H2O2 decomposition by GAC followed first-order kinetics, and the rate constants normalised by the GAC dosage (kn) were steady (1.6 × 10-3 L g-1 min-1) with variations in the GAC dosage and initial H2O2 concentration. Alkaline conditions favour H2O2 quenching. The content of basic groups exhibited a stronger correlation with the efficiency of GAC in quenching H2O2 than did the acidic groups， with their specific kn values being 8.9 and 2.4 min-1 M-1, respectively. The presence of chloride, sulfate, nitrate, and dissolved organic matter inhibited H2O2 quenching, while HCO3- promoted it. The interfacial hydroxyl radical (HO•) zones were visualised on the GAC surface, and HCO3- addition increased the HO• concentration. HCO3- increased the concentration of persistent free radicals (PFRs) on the GAC surface, which mainly contributed to HO• generation. A significant enhancement of HCO3- on H2O2 quenching by GAC was also verified in real water. This study revealed the synergistic mechanism of HCO3- and GAC on H2O2 quenching and presents the potential applications of residual H2O2 in the H2O2-based oxidation processes.

Technology for the formation of engineered microvascular network models and their biomedical applications.

Tissue engineering and regenerative medicine have made great progress in recent decades, as the fields of bioengineering, materials science, and stem cell biology have converged, allowing tissue engineers to replicate the structure and function of various levels of the vascular tree. Nonetheless, the lack of a fully functional vascular system to efficiently supply oxygen and nutrients has hindered the clinical application of bioengineered tissues for transplantation. To investigate vascular biology, drug transport, disease progression, and vascularization of engineered tissues for regenerative medicine, we have analyzed different approaches for designing microvascular networks to create models. This review discusses recent advances in the field of microvascular tissue engineering, explores potential future challenges, and offers methodological recommendations.

Spatiotemporal genotype replacement of H5N8 avian influenza viruses contributed to H5N1 emergence in 2021/2022 panzootic.

Since 2020, clade 2.3.4.4b highly pathogenic avian influenza H5N8 and H5N1 viruses have swept through continents, posing serious threats to the world. Through comprehensive analyses of epidemiological, genetic, and bird migration data, we found that the dominant genotype replacement of the H5N8 viruses in 2020 contributed to the H5N1 outbreak in the 2021/2022 wave. The 2020 outbreak of the H5N8 G1 genotype instead of the G0 genotype produced reassortment opportunities and led to the emergence of a new H5N1 virus with G1's HA and MP genes. Despite extensive reassortments in the 2021/2022 wave, the H5N1 virus retained the HA and MP genes, causing a significant outbreak in Europe and North America. Furtherly, through the wild bird migration flyways investigation, we found that the temporal-spatial coincidence between the outbreak of the H5N8 G1 virus and the bird autumn migration may have expanded the H5 viral spread, which may be one of the main drivers of the emergence of the 2020-2022 H5 panzootic.IMPORTANCESince 2020, highly pathogenic avian influenza (HPAI) H5 subtype variants of clade 2.3.4.4b have spread across continents, posing unprecedented threats globally. However, the factors promoting the genesis and spread of H5 HPAI viruses remain unclear. Here, we found that the spatiotemporal genotype replacement of H5N8 HPAI viruses contributed to the emergence of the H5N1 variant that caused the 2021/2022 panzootic, and the viral evolution in poultry of Egypt and surrounding area and autumn bird migration from the Russia-Kazakhstan region to Europe are important drivers of the emergence of the 2020-2022 H5 panzootic. These findings provide important targets for early warning and could help control the current and future HPAI epidemics.

Recent Developments in Layer-by-Layer Assembly for Drug Delivery and Tissue Engineering Applications.

Surfaces with biological functionalities are of great interest for biomaterials, tissue engineering, biophysics, and for controlling biological processes. The layer-by-layer (LbL) assembly is a highly versatile methodology introduced 30 years ago, which consists of assembling complementary polyelectrolytes or biomolecules in a stepwise manner to form thin self-assembled films. In view of its simplicity, compatibility with biological molecules, and adaptability to any kind of supporting material carrier, this technology has undergone major developments over the past decades. Specific applications have emerged in different biomedical fields owing to the possibility to load or immobilize biomolecules with preserved bioactivity, to use an extremely broad range of biomolecules and supporting carriers, and to modify the film's mechanical properties via crosslinking. In this review, the focus is on the recent developments regarding LbL films formed as 2D or 3D objects for applications in drug delivery and tissue engineering. Possible applications in the fields of vaccinology, 3D biomimetic tissue models, as well as bone and cardiovascular tissue engineering are highlighted. In addition, the most recent technological developments in the field of film construction, such as high-content liquid handling or machine learning, which are expected to open new perspectives in the future developments of LbL, are presented.

Ethanol-diluted turbidimetry method for rapid and accurate quantification of low-density microplastics in synthetic samples.

Retention and transport behaviours of microplastics (MPs) and their associated pollutants in porous media are of great concern. The homogeneity of the studied MPs in artificially controlled lab-scale studies makes rapid and accurate MP quantification feasible. In this study, an economical ethanol-diluted turbidimetry method for polypropylene (PP) and polyethylene (PE) MPs was developed. With ethanol dilution, the MP dispersion system exhibited an excellent suspension performance. Strong linear relationships were observed between MP concentrations and turbidities in both low (<1.3 mg L-1) and high (<170 mg L-1) MP concentration ranges. Solution density and MP agglomeration governed the MP suspension performance. For low surface tension and high molecular mass, the addition of ethanol decreased the contact angles of PP-MPs with solutions from 81.73 to 15.5°, and consequently improved the MP suspension performance. The suspension system was optimised to an ethanol/water (v/v) ratio of 3:2 and 4:1 for PP- and PE-MPs, when the slopes of standard curves were determined to be 1.252 and 0.471 with the recovery of 100.54 ± 3.09% and 103.19 ± 1.66%, and the limit of detection and quantification values of 0.025 and 0.082 mg L-1, and 0.060 and 0.201 mg L-1, respectively. Solution pH, salinity, and dissolved organic matter in the selected range induced acceptable fluctuations in the MP recovery and matrix effect values. The Derjaguin-Landau-Verwey-Overbeek (DLVO) energy barriers were calculated to be > 20 kT, indicating excellent tolerance to the solution matrix. Additionally, applications in real water samples were validated to demonstrate the potential of the developed method.

Control of blood capillary networks and holes in blood-brain barrier models by regulating elastic modulus of scaffolds.

The blood-brain barrier (BBB) is a type of capillary network characterized by a highly selective barrier, which restricts the transport of substances between the blood and nervous system. Numerous in vitro models of the BBB have been developed for drug testing, but a BBB model with controllable capillary structures remains a major challenge. In this study, we report for the first time a unique method of controlling the blood capillary networks and characteristic holes formation in a BBB model by varying the elastic modulus of a three-dimensional scaffold. The characteristic hole structures are formed by the migration of endothelial cells from the model surface to the interior, which have functions of connecting the model interior to the external environment. The hole depth increased, as the elastic modulus of the fibrin gel scaffold increased, and the internal capillary network length increased with decreasing elastic modulus. Besides, internal astrocytes and pericytes were also found to be important for inducing hole formation from the model surface. Furthermore, RNA sequencing indicated up-regulated genes related to matrix metalloproteinases and angiogenesis, suggesting a relationship between enzymatic degradation of the scaffolds and hole formation. The findings of this study introduce a new method of fabricating complex BBB models for drug assessment.

3D puzzle-inspired construction of large and complex organ structures for tissue engineering.

3D printing as a powerful technology enables the fabrication of organ structures with a programmed geometry, but it is usually difficult to produce large-size tissues due to the limited working space of the 3D printer and the instability of bath or ink materials during long printing sessions. Moreover, most printing only allows preparation with a single ink, while a real organ generally consists of multiple materials. Inspired by the 3D puzzle toy, we developed a "building block-based printing" strategy, through which the preparation of 3D tissues can be realized by assembling 3D-printed "small and simple" bio-blocks into "large and complex" bioproducts. The structures that are difficult to print by conventional 3D printing such as a picture puzzle consisting of different materials and colors, a collagen "soccer" with a hollow yet closed structure, and even a full-size human heart model are successfully prepared. The 3D puzzle-inspired preparation strategy also allows for a reasonable combination of various cells in a specified order, facilitating investigation into the interaction between different kinds of cells. This strategy opens an alternative path for preparing organ structures with multiple materials, large size and complex geometry for tissue engineering applications.

The high prevalence of occult hepatitis B infections among the partners of chronically infected HBV blood donors emphasizes the potential residual risk to blood safety.

A small percentage of couples who regularly donated blood in China tested positive for HBsAg. Although it is well known that blood donors can acquire hepatitis B virus (HBV) infection from a chronically infected sexual partner, the prevalence of occult hepatitis B infections (OBIs) among blood donations from partners of HBV-infected chronically infected spouses and the risk to blood safety remain poorly understood. Among 212 763 blood donors, 54 pairs of couples (108 donations) were enrolled because one partner tested positive for HBsAg. Several molecular and serological examinations were conducted. The origin of HBV transmission between sexual partners was investigated further. Also evaluated was the potential risk of HBV infection with OBIs. We identified 10 (10/54, 18.6%) sexual partners of chronically infected HBV donors who were positive for HBV DNA, including five samples (9.3%) with OBIs, of which 3 (3/54, 5.6%, 1 in 70 921 donations) passed the routine blood screening tests. Seven of the 10 HBV-DNA-positive couples contracted the virus possibly through sexual or close contact. Among infected couples, immune escape mutations were observed. A high prevalence of OBIs was found among the partners of chronically infected HBV blood donors, posing a potential threat to blood safety.

Characterizing the dynamics of BCR repertoire from repeated influenza vaccination.

Yearly epidemics of seasonal influenza cause an enormous disease burden around the globe. An understanding of the rules behind the immune response with repeated vaccination still presents a significant challenge, which would be helpful for optimizing the vaccination strategy. In this study, 34 healthy volunteers with 16 vaccinated were recruited, and the dynamics of the BCR repertoire for consecutive vaccinations in two seasons were tracked. In terms of diversity, length, network, V and J gene segments usage, somatic hypermutation (SHM) rate and isotype, it was found that the overall changes were stronger in the acute phase of the first vaccination than the second vaccination. However, the V gene segments of IGHV4-39, IGHV3-9, IGHV3-7 and IGHV1-69 were amplified in the acute phase of the first vaccination, with IGHV3-7 dominant. On the other hand, for the second vaccination, the changes were dominated by IGHV1-69, with potential for coding broad neutralizing antibody. Additional analysis indicates that the application of V gene segment for IGHV3-7 in the acute phase of the first vaccination was due to the elevated usage of isotypes IgM and IgG3. While for IGHV1-69 in the second vaccination, it was contributed by isotypes IgG1 and IgG2. Finally, 41 public BCR clusters were identified in the vaccine group, with both IGHV3-7 and IGHV1-69 were involved and representative complementarity determining region 3 (CDR3) motifs were characterized. This study provides insights into the immune response dynamics following repeated influenza vaccination in humans and can inform universal vaccine design and vaccine strategies in the future.

Construction of enzyme digested holes on hydrogel surface inspired by cell migration processes.

The construction of in vitro capillary network models for drug testing and toxicity evaluation has become a major challenge in the field of tissue engineering. Previously, we discovered a novel phenomenon of hole formation by endothelial cell migration on the surface of fibrin gels. Interestingly, the hole characteristics, such as depth and number, were strongly influenced by the gel stiffness, but the details of hole formation are not to be clarified. In this study, we tried to understand the effect of hydrogel stiffness on the hole formation by dropping collagenase solution onto the surface of the hydrogels because the endothelial cell migration was made possible by the metalloproteinases' digestion. We found that smaller hole structures were formed on stiffer fibrin gels, but larger ones were formed on softer fibrin gels after the hydrogel digestion of the collagenase. This is consistent with our previous results in experiments on hole structures formed by endothelial cells. Furthermore, deep and small hole structures were successfully obtained by optimizing the volume of collagenase solution and incubation time. This unique approach inspired by endothelial cell hole formation may provide new methods of fabricating hydrogels with opening hole structures.

Bioactivity of recombinant humanized monoclonal antibody against HER2 in-vivo and in-vitro and its mechanism of action in ovarian cancer.

Background: Human epidermal growth factor receptor 2 (HER2) protein is overexpressed on the surface of various epithelial ovarian cancer tissues, mediates the proliferation, differentiation, metastasis, and signal transduction of tumor cells, and thus is a potential cancer therapeutic target. However, its research in ovarian cancer is still limited, and how to quickly obtain a large number of antibodies remains a concern for researchers. Methods: In this study, we expressed the recombinant anti-HER2 humanized monoclonal antibody (rhHER2-mAb) in human embryonic kidney 293 (HEK293) cells through transient gene expression (TGE) technology by constructing a mammalian cell expression vector. Firstly, the transfection conditions has been optimized, the ratio of light chain (LC) and heavy chain (HC) was optimized in the range of 4:1 to 1:2 and the ration DNA and polyethyleneimine was optimized in the range of 4:1 to 1:1. The antibody was purified by rProtein A affinity chromatography, and its mediated antibody-dependent cellular cytotoxicity (ADCC) was identified by lactate dehydrogenase release assays. The anti-tumor activity of rhHER2-mAb was evaluated in non-obese diabetic/severe combined immunodeficiency mice. Results: The expression of rhHER2-mAb in the HEK293F cells was at the highest level (100.5 mg/L) when the DNA/polyethyleneimine and light-chain/heavy-chain ratios were 1:4 and 1:2, respectively. The half-maximal inhibitory concentration of the ADCC of the antibodies against the SK-OV-3, OVCAR-3, and A-2780 cells were 12.36, 5.43, and 102.90 ng/mL, respectively. The animal experiments with the mice showed that rhHER2-mAb effectively inhibited the growth (P<0.01) of the SK-OV-3 tumors at a dose of 10 mg/kg. Conclusions: TGE technology allows us to quickly obtain a large number of anti-HER2 antibodies compared to the traditional method of constructing stable cell lines, and its in vitro and in vivo studied shows that our anti-HER2 antibody have higher affinity and better biological activity bioactivity (P<0.01) compared to Herceptin. Our findings provide novel insights into the development and production of future biotechnology-based drugs using the TGE technology of HEK293F.

3D Printing of Collagen Scaffold with Enhanced Resolution in a Citrate-Modulated Gellan Gum Microgel Bath.

3D printing in a microgel-based supporting bath enables the construction of complex structures with soft and watery biomaterials but the low print resolution is usually an obstacle to its practical application in tissue engineering. Herein, high-resolution printing of a 3D collagen organ scaffold is realized by using an engineered Gellan gum (GG) microgel bath containing trisodium citrate (TSC). The introduction of TSC into the bath system not only mitigates the aggregation of GG microgels, leading to a more homogeneous bath morphology but also suppresses the diffusion of the collagen ink in the bath due to the dehydration effect of TSC, both of which contribute to the improvement of print resolution. 3D collagen organ structures such as hand, ear, and heart are successfully constructed with high shape fidelity in the developed bath. After printing, the GG and TSC can be easily removed by washing with water, and the obtained collagen product exhibits good cell affinity in a tissue scaffold application. This work offers an easy-to-operate strategy for developing a microgel bath for high-resolution printing of collagen, providing an alternative path to in vitro 3D organ construction.

Comparative analysis of the residues of granular support bath materials on printed structures in embedded extrusion printing.

Embedded extrusion printing facilitates the fabrication of complex biological structures using soft hydrogels that are challenging to construct using conventional manufacturing methods. While this targeting strategy is appealing, the residues of support materials on the printed objects have been overlooked. Here, we quantitatively compare the bath residues on fibrin gel fibers printed in granular gel baths that are conjugated with fluorescent probes for visualization, including physically crosslinked gellan gum (GG) and gelatin (GEL) baths and chemically crosslinked polyvinyl alcohol baths. Notably, all support materials can be detected on a microscopic scale, even on structures without any visible residues. Quantitative results indicate that baths with smaller size or lower shear viscosity show more and deeper diffusion into the extruded inks, and the removal efficiency of support materials depends mainly on the dissolving property of the granular gel baths. The residual amount of chemically cross-linked support materials on fibrin gel fibers is 28-70µg mm-2, which is tens of times higher than physically cross-linked GG (7.5µg mm-2) and GEL (0.3µg mm-2) baths. Meanwhile, cross-sectional images suggest that most gel particles are distributed around the fiber surface, but a small amount is in the fiber center. Such bath residues or the blank pores created by the removal of gel particles induce changes in product surface morphology, physicochemical and mechanical properties, impeding cell adhesion. This study will draw attention to the effects of residual support materials on printed structures and encourage the development of new strategies to diminish these residues or to take advantage of the residual support baths to improve product performances.

Variation in synonymous evolutionary rates in the SARS-CoV-2 genome.

Introduction: Coronavirus disease 2019 is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Influential variants and mutants of this virus continue to emerge, and more effective virus-related information is urgently required for identifying and predicting new mutants. According to earlier reports, synonymous substitutions were considered phenotypically silent; thus, such mutations were frequently ignored in studies of viral mutations because they did not directly cause amino acid changes. However, recent studies have shown that synonymous substitutions are not completely silent, and their patterns and potential functional correlations should thus be delineated for better control of the pandemic. Methods: In this study, we estimated the synonymous evolutionary rate (SER) across the SARS-CoV-2 genome and used it to infer the relationship between the viral RNA and host protein. We also assessed the patterns of characteristic mutations found in different viral lineages. Results: We found that the SER varies across the genome and that the variation is primarily influenced by codon-related factors. Moreover, the conserved motifs identified based on the SER were found to be related to host RNA transport and regulation. Importantly, the majority of the existing fixed-characteristic mutations for five important virus lineages (Alpha, Beta, Gamma, Delta, and Omicron) were significantly enriched in partially constrained regions. Discussion: Taken together, our results provide unique information on the evolutionary and functional dynamics of SARS-CoV-2 based on synonymous mutations and offer potentially useful information for better control of the SARS-CoV-2 pandemic.

Demographic Factors Among HIV Confirmed Blood Donors from 2013 to 2021 in Shenzhen.

Background: New HIV (Human immune deficiency virus) infections are continuously increasing in China and it remains a huge challenge to blood donation. As access to health services has affected by COVID-19 (Corona virus disease 2019) pandemic, a drop in new diagnoses (especially HIV) was observed worldwide. Methods: During 2013-2021, 735,247 specimens from unpaid blood donors collected by Shenzhen Blood Center underwent ELISA (Enzyme -linked immunosorbent assay) and NAT (Nucleic acid test). Samples with reactivity results were sent to the Shenzhen Center for Disease Control and Prevention for WB (Western blot). All data were statistically analyzed by the Chi-Square test. Results: From 2013 to 2021, the prevalence of HIV among male blood donors was higher than in females (P < 0.01). During the COVID-19 pandemic, the prevalence of HIV among repeat blood donors decreased significantly compared to 2019 (P < 0.05), and the characteristics of blood donors changed in 2020 compared to 2019 and 2021. Conclusion: The high proportion of female blood donors would help prevent HIV from getting into the blood supply. The COVID-19 pandemic affected the demographics of blood donors as well as the prevalence of HIV among repeat blood donors. An increased number of repeat blood donors can help decrease the risk of HIV transfusion transmission during the epidemic.

"Out-of-the-box" Granular Gel Bath Based on Cationic Polyvinyl Alcohol Microgels for Embedded Extrusion Printing.

Embedded extrusion printing provides a versatile platform for fabricating complex hydrogel-based biological structures with living cells. However, the time-consuming process and rigorous storage conditions of current support baths hinder their commercial application. This work reports a novel "out-of-the-box" granular support bath based on chemically crosslinked cationic polyvinyl alcohol (PVA) microgels, which is ready to use by simply dispersing the lyophilized bath in water. Notably, with ionic modification, PVA microgels yield reduced particle size, uniform distribution, and appropriate rheological properties, contributing to high-resolution printing. Following by the lyophilization and re-dispersion process, ion-modified PVA baths recover to its original state, with unchanged particle size, rheological properties, and printing resolution, demonstrating its stability and recoverability. Lyophilization facilitates the long-term storage and delivery of granular gel baths, and enables the application of "out-of-the-box" support materials, which will greatly simplify experimental procedures, avoid labor-intensive and time-consuming operations, thus accelerating the broad commercial development of embedded bioprinting.

Interactions between H2O2 and dissolved organic matter during granular activated carbon-based residual H2O2 quenching from the upstream UV/H2O2 process.

Granular activated carbon (GAC) filtration can be employed to synchronously quench residual H2O2 from the upstream UV/H2O2 process and further degrade dissolved organic matter (DOM). In this study, rapid small-scale column tests (RSSCTs) were performed to clarify the mechanisms underlying the interactions between H2O2 and DOM during the GAC-based H2O2 quenching process. It was observed that GAC can catalytically decompose H2O2, with a long-lasting high efficiency (>80% for approximately 50,000 empty-bed volumes). DOM inhibited GAC-based H2O2 quenching via a pore-blocking effect, especially at high concentrations (10 mg/L), with the adsorbed DOM molecules being oxidized by the continuously generated ·OH; this further deteriorated the H2O2 quenching efficiency. In batch experiments, H2O2 could enhance DOM adsorption by GAC; however, in RSSCTs, it deteriorated DOM removal. This observation could be attributed to the different ·OH exposure in these two systems. It was also observed that aging with H2O2 and DOM altered the morphology, specific surface area, pore volume, and the surface functional groups of GAC, owing to the oxidation effect of H2O2 and ·OH on the GAC surface as well as the effect of DOM. Additionally, the changes in the content of persistent free radicals in the GAC samples were insignificant following different aging processes. This work contributes to enhancing understanding regarding the UV/H2O2-GAC filtration scheme, and promoting the application in drinking water treatment.