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Complex tissue damage accompanying with bacterial infection challenges healthcare systems globally. Conventional tissue engineering scaffolds normally generate secondary implantation trauma, mismatched regeneration and infection risks. Herein, we developed an easily implanted scaffold with multistep shape memory and photothermal-chemodynamic properties to exactly match repair requirements of each part from the tissue defect by adjusting its morphology as needed meanwhile inhibiting bacterial infection on demand. Specifically, a thermal-induced shape memory scaffold was prepared using hydroxyethyl methacrylate and polyethylene glycol diacrylate, which was further combined with the photothermal agent iron tannate (FeTA) to produce NIR light-induced shape memory property. By varying ingredients ratios in each segment, this scaffold could perform a stepwise recovery under different NIR periods. This process facilitated implantation after shape fixing to avoid trauma caused by conventional methods and gradually filled irregular defects under NIR to perform suitable tissue regeneration. Moreover, FeTA also catalyzed Fenton reaction at bacterial infections with abundant H2O2, which produced excess ROS for chemodynamic antibacterial therapy. As expected, bacteriostatic rate was further enhanced by additional photothermal therapy under NIR. The in vitro and vivo results showed that our scaffold was able to perform high efficacy in both antibiosis, inflammation reduction and wound healing acceleration, indicating a promising candidate for the regeneration of complex tissue damage with bacterial infection.

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OBJECTIVE: Understanding the differences of suprasellar papillary and adamantinomatous craniopharyngiomas (PCPs/ACPs) is pivotal for target therapy, surgical strategy or postoperative management. Here, the clinical features, surgical nuances and postoperative hypothalamic outcomes of PCPs were systematically recapitulated. METHODS: 24 PCPs and 52 ACPs underwent initial surgery were retrospectively reviewed. Clinical data, quantified third ventricle (3rd V) occupation and optic chiasm distortion were compared, as well as intra-operative findings, operating notes and prognosis. Moreover, analysis of tumor/3rd V relationship and hypothalamic outcomes were also performed. RESULTS: Tumors were more likely to occupies the 3rd V cavity in PCPs. Chiasm distortion of "compressed forward" was the most common pattern (45.8 %) in PCPs, whereas "stretched forward" pattern accounted the highest (42.5 %) in ACPs. Besides, round-shaped with less calcification, duct-like recess, solid consistency, rare subdiaphragmatic invasion, visible lower stalk and improved postoperative visual outcome were more frequently observed in PCPs. The basal membranes of the tumor epithelium and the reactive gliosis were separated by a layer of collagen fibers in most PCPs, which differs from ACPs in the morphological examination of tumor/3rd V floor interface. In daytime sleepiness and memory difficulty, the PCPs showed significantly better outcomes than the ACPs groups, and PCPs suffered less postoperative weight gain (p < 0.05) than ACPs among adult-onset cases. CONCLUSION: PCPs are different from ACPs regards the clinical features, operative techniques and outcomes. If necessary, PCPs are suggested more amenable to total removal since its less invasiveness to the 3rd V floor and better hypothalamic outcomes.

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The high water solubility and flammability of polyvinyl alcohol (PVA) limits its further widespread use in areas such as bioplastic and green packaging. In this study, double-crosslinked polyvinyl alcohol/starch bioplastics (named PDA) were fabricated using PVA, dialdehyde starch (DAS), and phytic acid (PA), resulting in a material with superior water resistance, flame retardancy, and excellent degradability. PA not only plays the role of catalyst for the chemical crosslinking but also as the physical crosslinker to form the intermolecular hydrogen bonds with PVA and DAS. This chemically and physically double cross-linked network structure results in PDA bioplastics with excellent toughness and water resistance. Specifically, the optimal formulation with 15 % PA content, designated as PDA15, exhibited a high toughness of 35.5 MJ/m3 and demonstrated prolonged shape retention in the boiling water. Additionally, PA also serves as a flame-retardant and antibacterial agent; the PDA15 achieved a high limit oxygen index (LOI) value of 40.0 % and passed the UL-94 V-0 rating without melt dripping, along with better degradability compared to pure PVA film. These outstanding performances make the PDA bioplastics highly promising for various applications, particularly in disposable plastics and laminated flexible packaging materials.

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BACKGROUND: Early dissemination to distant organs accounts for the dismal prognosis of patients with pancreatic ductal adenocarcinoma (PDAC). Chronic, dysregulated, persistent and unresolved inflammation provides a preferred tumor microenvironment (TME) for tumorigenesis, development, and metastasis. A better understanding of the key regulators that maintain inflammatory TME and the development of predictive biomarkers to identify patients who are most likely to benefit from specific inflammatory-targeted therapies is crucial for advancing personalized cancer treatment. METHODS: This study identified cell-specific expression of CALB2 in human PDAC through single-cell RNA sequencing analysis and assessed its clinicopathological correlations in tissue microarray using multi-color immunofluorescence. Co-culture systems containing cancer-associated fibroblasts (CAFs) and patient-derived organoids (PDOs) in vitro and in vivo were employed to elucidate the effects of CALB2-activated CAFs on PDAC malignancy. Furthermore, CUT&RUN assays, luciferase reporter assays, RNA sequencing, and gain- or loss-of-function assays were used to unravel the molecular mechanisms of CALB2-mediated inflammatory reprogramming and metastasis. Additionally, immunocompetent KPC organoid allograft models were constructed to evaluate CALB2-induced immunosuppression and PDAC metastasis, as well as the efficacy of inflammation-targeted therapy. RESULTS: CALB2 was highly expressed both in CAFs and cancer cells and correlated with an unfavorable prognosis and immunosuppressive TME in PDAC patients. CALB2 collaborated with hypoxia to activate an inflammatory fibroblast phenotype, which promoted PDAC cell migration and PDO growth in vitro and in vivo. In turn, CALB2-activated CAFs upregulated CALB2 expression in cancer cells through IL6-STAT3 signaling-mediated direct transcription. In cancer cells, CALB2 further activated Ca2+-CXCL14 inflammatory axis to facilitate PDAC metastatic outgrowth and immunosuppression. Genetic or pharmaceutical inhibition of CXCL14 significantly suppressed CALB2-mediated metastatic colonization of PDAC cells in vivo and extended mouse survival. CONCLUSIONS: These findings identify CALB2 as a key regulator of inflammatory reprogramming to promote PDAC metastatic progression. Combination therapy with αCXCL14 monoclonal antibody and gemcitabine emerges as a promising strategy to suppress distant metastasis and improve survival outcomes in PDAC with CALB2 overexpression.

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In this paper, we demonstrate stable radio frequency (RF) transfer via metropolitan optical fiber link in the Beijing area. The phase variation of the RF signal is compensated by a phase conjugation method incorporating two high-performance phase-locked loops. The wavelength conversion module extends the transmission length to 200 km with only two parallel 50 km dark optical fibers available. We optimize the configuration of dispersion compensation and optical amplification due to the high loss (0.31 dB/km) of the optical fiber link. At the same time, comparative experiments verify the short-term instability limitation that arises from the group velocity dispersion of the optical fiber link. The measured standard Allan deviation of the 2.4 GHz RF transmission system with dispersion compensation is 4.5 × 10-14/1 and 2.6 × 10-17/20 000 s, which is superior to that of the reference rubidium clock. The short-term instability of the system is deteriorated to 2.5 × 10-13/1 s without dispersion compensation.

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The photocatalytic degradation of polychlorinated biphenyls (PCBs) is advancing, yet the efficiency of degradation within the visible spectral range continues to encounter significant challenges. In this study, two biochar-based organic semiconductor photocatalysts, Active Carbon@PTQ10 (5,8-Dibromo-6,7-difluoro-2-(2-hexyldecoxy)quinoxaline; trimethyl-(5-trimethylstannylthiophen-2-yl)stannane): ITIC-Th (Propanedinitrile,2,2'-[[6,6,12,12-tetrakis(5-hexyl-2-thienyl)-6,12-dihydrodithieno[2,3-d: 2',3'-d'] -s-indaceno[1,2-b:5,6-b'] dithiophene-2,8-diyl] bis[methylidyne(3-oxo-1H-indene-2,1(3H)-diylidene)]] bis-) (AC@PI) and Active Carbon@PTQ10: PC71BM (6,6)-phenyl C71 butyric acid methyl ester), were synthesized using a wide bandgap material, PTQ10, as the electron donor, along with a non-fullerene material, ITIC-Th, and a fullerene material, PC71BM, as the acceptors, respectively. Under optimized conditions, AC@PI degraded 93.4 % of 2,2 ',4,4 '-tetrachlorobiphenyl (PCB 47) within 60 min. By incorporating a non-fullerene acceptor (ITIC-Th), AC@PI exhibits a larger surface photopressure, a lower hole-electron transfer ratio, a broader absorption spectrum (400 - 1000 nm), and enhanced structural stability. AC@PI can generate photogenerated electrons and holes, as well as superoxide anions (O2-) and hydroxyl radicals (OH), through type II heterojunctions, which contributes to its exceptional properties. This study synthesized novel organic semiconductor catalysts that offer a green, efficient, and non-toxic method for the degradation of aromatic pollutants, such as polychlorinated biphenyls.

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OBJECTIVE: To compare the clinical and radiographic outcomes of single-segment posterior decompression combined with two different non-fusion dynamic stabilization systems, Isobar EVO and Isobar TTL, in the context of facet joint degeneration and segmental mobility. METHOD: A retrospective study was conducted on 47 patients who underwent single-segment surgery at the L4/5 level using either the Isobar EVO (n = 23) or Isobar TTL (n = 24) systems. We assessed facet joint degeneration on both sides of the fixed (L3/4, L4/5) and superior adjacent (L2/3) segments using the Fujiwara MRI grading system. Clinical outcomes were evaluated using the Oswestry Disability Index (ODI) and visual analog scale (VAS) for back and leg pain at baseline, 12 months, and 24 months postoperatively. RESULT: Both groups exhibited significant facet joint degeneration at the fixed segments (L3/4 and L4/5) at 24 months. The TTL group also showed significant degeneration at the superior adjacent segment (L2/3), whereas the EVO group did not. Restoration of lumbar lordosis was significantly better in the EVO group. Pain and disability scores improved more in the EVO group than in the TTL group at both 12 and 24 months postoperatively. CONCLUSION: The Isobar EVO system, with its enhanced mobility, may delay facet joint degeneration in the superior adjacent segment compared to the Isobar TTL system. However, both systems result in degeneration at the fixed segment, indicating a need for further improvements to mimic the natural biomechanics of the spine more closely.

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We present here a novel paired electrocatalysis-enabled convenient synthesis of the (E)-vinyl sulfoximines through the cross-coupling reaction of sulfinamides and olefins. This protocol showed a broad substrate scope and excellent E selectivity of products under metal- and oxidant-free conditions. A preliminary mechanistic study suggested that fluorinated sulfoximine generated from anodic oxidation of sulfinamide was the key intermediate that was then converted into the sulfonimidoyl radical at the cathode with the help of DBU in this reaction.

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This clinical trial examined the individual and combined effects of three different approaches to reducing alcohol misuse among a sample of sexual minority men (SMM) with HIV. Specifically, we used a 2 × 2 × 2 randomized factorial design to compare: (a) behavioral intervention based in motivational interviewing (MI) vs. brief intervention (BI), (b) interactive text messaging (ITM) for alcohol use vs. no ITM, and (c) extended intervention (EI) length of nine months vs. a one-month intervention duration. Participants (N = 188) were SMM with HIV and alcohol misuse recruited in Miami, FL, and Boston, MA. Participants were randomized to one of eight intervention combinations and assessed at 6- and 12-month follow-ups. Large reductions of over 50% in drinks per week and heavy drinking days were observed in all conditions at follow-up. Those who received ITM, compared to those who did not, reported significantly lower drinks consumed per week at 6 and 12 months (incidence rate ratios = 0.73 [95% CI = 0.57, 0.90] and 0.72 [95% CI = 0.56, 0.87], respectively), and increased odds of cessation of alcohol misuse at 12 months, odds ratio = 1.46, 95% CI = 1.03, 2.08. Results provided no evidence of better alcohol use outcomes for either MI or EI relative to their comparison conditions, and no specific combination of intervention components demonstrated a notable benefit. This study suggests a two-session BI can effectuate substantial reductions in alcohol use in SMM with HIV and that adding one month of ITM can yield further improvements. Clinical Trials Number: NCT02709759.

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Purpose: To develop a Vision Transformer (ViT) model based on the mixed attention feature enhancement mechanism, ChoroidSeg-ViT, for choroid layer segmentation in optical coherence tomography (OCT) images. Methods: This study included a dataset of 100 OCT B-scans images. Ground truths were carefully labeled by experienced ophthalmologists. An end-to-end local-enhanced Transformer model, ChoroidSeg-ViT, was designed to segment the choroid layer by integrating the local enhanced feature extraction and semantic feature fusion paths. Standard segmentation metrics were selected to evaluate ChoroidSeg-ViT. Results: Experimental results demonstrate that ChoroidSeg-ViT exhibited superior segmentation performance (mDice: 98.31, mIoU: 96.62, mAcc: 98.29) compared to other deep learning approaches, thus indicating the effectiveness and superiority of this proposed model for the choroid layer segmentation task. Furthermore, ablation and generalization experiments validated the reasonableness of the module design. Conclusions: We developed a novel Transformer model to precisely and automatically segment the choroid layer and achieved the state-of-the-art performance. Translational Relevance: ChoroidSeg-ViT could segment precise and smooth choroid layers and form the basis of an automatic choroid analysis system that would facilitate future choroidal research in ophthalmology.

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The purpose of this study was to investigate the role of polysaccharides from Ostrea rivularis Gloud (ORPs) in the progression of diabetic retinopathy (DR) and its anti-angiogenic effect on endothelial cell. Transgenic db/db mice with DR model were used to evaluate the protective effect of ORPs on retinal damage. It was found that ORPs could down-regulated levels of random blood glucose and fasting insulin, and further ameliorate retinal structure abnormalities as well as vascular network structure. Moreover, ORPs could reduce the expression of VEGF in retinal tissue and lessen pathological angiogenesis, thus slowing the progression of DR. In vitro, the proliferation, migration and tube formation of VGEF165-induced EA.hy926 cells were inhibited with ORPs administration. Furthermore, the expression of related proteins in the PI3K/AKT pathway and angiogenesis related factors were improved after ORPs intervention. Overall, these findings suggested that ORPs could effectively control the development of DR, and inhibit VGEF165-induced EA.hy926 cells proliferation, migration and tube formation, which effects might work through blocking the activation of PI3K/AKT signaling pathway.

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All-solid-state (ASS) lithium-sulfur (LiS) batteries utilizing composite polymer electrolytes (CPEs) represent a promising avenue in the domain of electric vehicles and large-scale energy storage systems, leveraging the combined benefits of polymer electrolytes (PEs) and ceramic electrolytes (CEs). However, the inherent weak interface compatibility between PEs and CEs often leads to phase separation, thereby impeding the transposition of Li+. In this study, the trimethoxy-[3-(2-methoxyethoxy)propyl]silane (TM-MES) is introduced as a chemical agent to form bonds with polyethylene oxide (PEO) and Li10GeP2S12 (LGPS), resulting in the development of a novel composite polymer electrolyte (CPETM-MES). This innovative approach mitigates phase separation between PEs and CEs while concurrently enhancing the protective capabilities of LGPS against decomposition at the interfaces of both the Li anode and sulfur cathode. Moreover, the CPETM-MES exhibits superior mechanical toughness, an expanded electrochemical window, and elevated ionic conductivity. In the symmetric cell, it demonstrates an extended operational lifespan exceeding 1800 h, and the current density can reach up to 1.05 mA/cm2. Furthermore, the initial discharge capacity of ASS LiS batteries utilizing CPETM-MES attains 1227 mAh/g and maintains a capacity of 904 mAh/g after 100 cycles. Notably, a high-energy-density of 2454 Wh/kg is achieved based on the sulfur cathode.

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Against the backdrop of rapid advancements in 5G and Internet of Things (IoT) technologies, there is an urgent need to upgrade food sensing systems to achieve automation, digitalization, and intelligence. However, this transformation process faces numerous challenges. Triboelectric nanogenerators (TENGs), as an emerging energy conversion and sensing technology, play a crucial role in this context. They not only provide power to functional devices but also serve as sensors in multifunctional self-powered food sensing systems, capable of detecting various physical and chemical information. This review explores the development of TENGs in the field of food sensing, focusing on the working principles of their self-powered sensing. The review also systematically organizes and classifies the material and device designs used for TENGs in various food applications. Based on the performance of TENGs, a detailed introduction is provided on the specific applications of self-powered food sterilization, self-powered food quality monitoring, and self-powered taste sensing in the field of food safety. Finally, this paper discusses the challenges and corresponding strategies of TENGs in the food sensing field. The aim is to further promote unmanned and smart services and management in the food sector and to provide new research perspectives.

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Titanium-based implants, renowned for their excellent mechanical properties, corrosion resistance, and biocompatibility, have found widespread application as premier implant materials in the medical field. However, as bioinert materials, they often face challenges such as implant failure caused by bacterial infections and inadequate osseointegration post-implantation. Thus, to address these issues, researchers have developed various surface modification techniques to enhance the surface properties and bioactivity of titanium-based implants. This review aims to outline several key surface modification methods for titanium-based implants, including acid etching, sol-gel method, chemical vapor deposition, electrochemical techniques, layer-by-layer self-assembly, and chemical grafting. It briefly summarizes the advantages, limitations, and potential applications of these technologies, presenting readers with a comprehensive perspective on the latest advances and trends in the surface modification of titanium-based implants.

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BACKGROUND: Body roundness index (BRI) is an anthropometric measure related to obesity, combining waist circumference (WC) and height to more accurately reflect body fat. This study aims to investigate the relationship between BRI and the risk of hypertension using data from a prospective cohort study in Southwest China. METHODS: Data for the study were derived from Guizhou Population Health Cohort Study (GPHCS), established in 2010. A total of 9,280 participants (aged 18 to 95 years, mean 41.53 ± 14.15 years) from 48 townships across 12 districts/counties were surveyed at baseline through multistage stratified random cluster sampling. Cox proportional risk models were employed to analyze the association between BRI and the risk of hypertension, estimating hazard ratios (HRs) and 95% confidence intervals (CIs) after adjusting for confounding factors. The relationship between BRI and the onset time of hypertension was analyzed using the time failure acceleration model. RESULTS: Over a median follow-up period of 6.64 years, 1,157 participants were diagnosed with hypertension. After adjusting for confounding variables, each unit increase in BRI was associated with a 17% increase in hypertension risk (HR = 1.17, 95% CI: 1.11, 1.24, P for trend < 0.001). Compared to participants in the first quartile (Q1) of BRI, the risk of hypertension for those in the third quartile (Q3) and fourth quartile (Q4) was 1.31 (95% CI: 1.10, 1.56) and 1.53 (95% CI: 1.28, 1.84), respectively. Each unit increase in BRI advanced the onset of hypertension by 0.26 years (95% CI: 0.16, 0.35). CONCLUSION: This study indicates that BRI has a positive association with hypertension and can accelerate the onset of hypertension in the Chinese population. It is suggested that reducing BRI by controlling abdominal fat may be one of the effective measure to prevent hypertension.

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Ultrafast lasers have become powerful tools in various fields, and increasing their fundamental repetition rates to the gigahertz (GHz) level holds great potential for frontier scientific and industrial applications. Among various schemes, passive mode-locking in ultrashort-cavity fiber laser is promising for generating GHz ultrashort pulses (typically solitons), for its simplicity and robustness. However, its pulse energy is far lower than the critical value of the existing theory, leading to open questions on the mode-locking mechanism of GHz fiber lasers. Here, we study the passive mode-locking in GHz fiber lasers by exploring dynamic gain depletion and recovery (GDR) effect, and establish a theoretical model for comprehensively understanding its low-threshold mode-locking mechanism with multi-GHz fundamental repetition rates. Specifically, the GDR effect yields an effective interaction force and thereby binds multi-GHz solitons to form a counterpart of soliton crystals. It is found that the resulting collective behavior of the solitons effectively reduces the saturation energy of the gain fiber and permits orders of magnitude lower pulse energy for continuous-wave mode-locking (CWML). A new concept of quasi-single soliton defined in a strongly correlated length is also proposed to gain insight into the dynamics of soliton assembling, which enables the crossover from the present mode-locking theory to the existing one. Specifically, two distinguishing dynamics of Q-switched mode-locking that respectively exhibit rectangular- and Gaussian-shape envelopes are theoretically indicated and experimentally verified in the mode-locked GHz fiber laser through the measurements using both the standard real-time oscilloscope and emerging time-lens magnification. Based on the proposed criterion of CWML, we finally implement a GDR-mediated mode-locked fiber laser with an unprecedentedly high fundamental repetition rate of up to 21 GHz and a signal-to-noise ratio of 85.9 dB.

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Weeds are undesired plants competing with crops for light, nutrients, and water, negatively impacting crop growth. Identifying weeds in wheat fields accurately is important for precise pesticide spraying and targeted weed control. Grass weeds in their early growth stages look very similar to wheat seedlings, making them difficult to identify. In this study, we focused on wheat fields with varying levels of grass weed infestation and used unmanned aerial vehicles (UAVs) to obtain images. By utilizing deep learning algorithms and spectral analysis technology, the weeds were identified and extracted accurately from wheat fields. Our results showed that the precision of weed detection in scattered wheat fields was 91.27% and 87.51% in drilled wheat fields. Compared to areas without weeds, the increase in weed density led to a decrease in wheat biomass, with the maximum biomass decreasing by 71%. The effect of weed density on yield was similar, with the maximum yield decreasing by 4320 kg·ha- 1, a drop of 60%. In this study, a method for monitoring weed occurrence in wheat fields was established, and the effects of weeds on wheat growth in different growth periods and weed densities were studied by accurately extracting weeds from wheat fields. The results can provide a reference for weed control and hazard assessment research.

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The mussel thread-plaque system exhibits strong adhesion and high deformability, allowing it to adhere to various surfaces. While the microstructure of plaques has been thoroughly studied, the effect of their unique porous structure on the high deformability remains unclear. This study first investigated the porous structure of mussel plaque cores using scanning electron microscopy (SEM). Two-dimensional (2D) porous representative volume elements (RVEs) with scaled distribution parameters were generated, and the calibrated phase-field modelling method was applied to analyse the effect of the pore distribution and multi-scale porous structure on the failure mechanism of porous RVEs. The SEM analysis revealed that large-scale pores exhibited a lognormal size distribution and a uniform spatial distribution. Simulations showed that increasing the normalised mean radius value (u) of the large-scale pore distribution can statistically lead to a decreasing trend in final failure strain, strength and strain energy density but cannot solely determine their values. The interaction between pores can lead to two different failure modes under the same pore distribution: progressive failure mode and sudden failure mode. Additionally, the hierarchical structure of multi-scale porous RVEs can further increase the final failure strain by 40-60% compared to single-scale porous RVEs by reducing stiffness, highlighting the hierarchical structure could be another key factor contributing to the high deformability. These findings deepen our understanding of how the pore distribution and multi-scale porous structure in mussel plaques contribute to their high deformability and affect other mechanical properties, providing valuable insights for the future design of highly deformable biomimetic materials.

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OBJECTIVE: Studies have shown that fine particulate matter (PM2.5) has adverse effects on the liver function, but epidemiological evidence is limited, especially regarding pregnant women. This study aims to investigate the association between PM2.5 exposure in early pregnancy and maternal liver function during pregnancy. METHODS: This retrospective cohort study included 13,342 pregnant participants. PM2.5 and Ozone (O3) exposure level, mean temperature, and relative humidity for each participant were assessed according to their residential address. The levels of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and total bilirubin (TBIL) were measured during the second and third trimesters. Data on PM2.5 and O3 exposure level were sourced from Tracking Air Pollution in China (TAP), while the mean temperature and relative humidity were obtained from the ERA5 dataset. The Generalized Additive Model (GAM) was used to analyze the associations between PM2.5 exposure and maternal liver function during pregnancy, adjusting for potential confounding factors. RESULTS: According to the results, each 10 µg/m3 increase in PM2.5 was associated with an increase of 3.57% (95% CI: 0.29%, 6.96%) in ALT and 4.25% (95% CI: 2.33%, 6.21%) in TBIL during the second trimester and 4.51% (95% CI: 2.59%, 6.47%) in TBIL during the third trimester, respectively. After adjusting for O3, these associations remained significant, and the effect of PM2.5 on ALT during the second trimester was further strengthened. No significant association observed between PM2.5 and AST. CONCLUSIONS: PM2.5 exposure in early pregnancy is associated with increasement of maternal ALT and TBIL, suggesting that PM2.5 exposure may have an adverse effect on maternal liver function. Although this finding indicates an association between PM2.5 exposure and maternal liver function, more research is needed to confirm our findings and explore the underlying biological mechanisms.

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Vanadium flow batteries (VFBs) are considered one of the most promising candidates for large-scale energy storage. However, VFBs suffer from relatively low power density due to severe electrochemical polarization. Herein, we report Bi single atoms supported by an N-doped carbon-regulated graphite felt electrode (Bi SAs/NC@GF) with high electrocatalytic activity and stability, owing to the greatly improved active sites and optimized Bi-N4 configuration. Electrochemical in situ characterization and theoretical calculations elucidate the desolvation process and specific inner sphere reaction mechanism of [V(H2O)6]3+/[V(H2O)6]2+. As a result, a VFB single cell assembled with Bi SAs/NC@GF achieves a much higher energy efficiency of 81.1% at 240 mA cm-2 than NC@GF (70.5%). Moreover, a 5 kW VFB stack equipped with Bi SAs/NC@GF is assembled for the first time and ran stably for over 400 cycles. This work confirms that a single-atom catalyst is efficient for scalable VFBs with high power density and low cost.