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Epstein-Barr virus (EBV) is a member of the lymphotropic virus family and is highly correlated with some human malignant tumors. It has been reported that envelope glycoprotein 110 (gp110) plays an essential role in viral fusion, DNA replication, and nucleocapsid assembly of EBV. However, it has not been established whether gp110 is involved in regulating the host's innate immunity. In this study, we found that gp110 inhibits tumor necrosis factor α-mediated NF- κB promoter activity and the downstream production of NF- κB-regulated cytokines under physiological conditions. Using dual-luciferase reporter assays, we showed that gp110 might impede the NF-κB promoter activation downstream of NF-κB transactivational subunit p65. Subsequently, we used coimmunoprecipitation assays to demonstrate that gp110 interacts with p65 during EBV lytic infection, and that the C-terminal cytoplasmic region of gp110 is the key interaction domain with p65. Furthermore, we determined that gp110 can bind to the N-terminal Rel homologous and C-terminal domains of p65. Alternatively, gp110 might not disturb the association of p65 with nontransactivational subunit p50, but we showed it restrains activational phosphorylation (at Ser536) and nuclear translocation of p65, which we also found to be executed by the C-terminal cytoplasmic region of gp110. Altogether, these data suggest that the surface protein gp110 may be a vital component for EBV to antagonize the host's innate immune response, which is also helpful for revealing the infectivity and pathogenesis of EBV.
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Infecções por Vírus Epstein-Barr , NF-kappa B , Humanos , NF-kappa B/genética , NF-kappa B/metabolismo , Herpesvirus Humano 4/metabolismo , Infecções por Vírus Epstein-Barr/genética , Fator de Transcrição RelA/genética , Fator de Transcrição RelA/metabolismo , Transdução de Sinais , Transporte ProteicoRESUMO
Botulinum neurotoxins (BoNTs), including serotypes A and E, are potent biotoxins known to cause human poisoning. In addition to the critical protective antigen found in the full BoNT molecule, the receptor binding domain (Hc domain), BoNTs also harbour another essential protective antigen-the light chain-translocation domain (L-HN domain). Leveraging these pivotal protective antigens, we genetically engineered a series of inactivated chimeric molecules incorporating L-HN and Hc domains of BoNT/A and E. The structure of these chimeric molecules, mirror BoNT/A and E, but are devoid of enzyme activity. Experimental findings demonstrated that a lead candidate mEL-HN-mAHc harnessing the inactivated protease LCHN/E with the mutated gangliosides binding site Hc/A (mE-mA) elicited robust immune protection against BoNT/A and E simultaneously in a mouse model, requiring low immune dosages and minimal immunisations. Moreover, mE-mA exhibited high protective efficacy against BoNT/A and E in guinea pigs and New Zealand white rabbits, resulting in elevated neutralising antibody titres. Furthermore, mE-mA proved to be a more stable and safer vaccine compared to formaldehyde-inactivated toxoid. Our data underscore the genetically engineered mE-mA as a highly effective bivalent vaccine against BoNT/A and E, paving the way for the development of polyvalent vaccines against biotoxins.
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INTRODUCTION: It was hypothesized that use of proton beam therapy (PBT) in patients with locally advanced non-small cell lung cancer treated with concurrent chemoradiation and consolidative immune checkpoint inhibition is associated with fewer unplanned hospitalizations compared with intensity-modulated radiotherapy (IMRT). METHODS: Patients with locally advanced non-small cell lung cancer treated between October 2017 and December 2021 with concurrent chemoradiation with either IMRT or PBT ± consolidative immune checkpoint inhibition were retrospectively identified. Logistic regression was used to assess the association of radiation therapy technique with 90-day hospitalization and grade 3 (G3+) lymphopenia. Competing risk regression was used to compare G3+ pneumonitis, G3+ esophagitis, and G3+ cardiac events. Kaplan-Meier method was used for progression-free survival and overall survival. Inverse probability treatment weighting was applied to adjust for differences in PBT and IMRT groups. RESULTS: Of 316 patients, 117 (37%) received PBT and 199 (63%) received IMRT. The PBT group was older (p < .001) and had higher Charlson Comorbidity Index scores (p = .02). The PBT group received a lower mean heart dose (p < .0001), left anterior descending artery V15 Gy (p = .001), mean lung dose (p = .008), and effective dose to immune circulating cells (p < .001). On inverse probability treatment weighting analysis, PBT was associated with fewer unplanned hospitalizations (adjusted odds ratio, 0.55; 95% CI, 0.38-0.81; p = .002) and less G3+ lymphopenia (adjusted odds ratio, 0.55; 95% CI, 0.37-0.81; p = .003). There was no difference in other G3+ toxicities, progression-free survival, or overall survival. CONCLUSIONS: PBT is associated with fewer unplanned hospitalizations, lower effective dose to immune circulating cells and less G3+ lymphopenia compared with IMRT. Minimizing dose to lymphocytes may be warranted, but prospective data are needed.
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Carcinoma Pulmonar de Células não Pequenas , Quimiorradioterapia , Hospitalização , Neoplasias Pulmonares , Terapia com Prótons , Radioterapia de Intensidade Modulada , Humanos , Carcinoma Pulmonar de Células não Pequenas/radioterapia , Carcinoma Pulmonar de Células não Pequenas/terapia , Carcinoma Pulmonar de Células não Pequenas/patologia , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Radioterapia de Intensidade Modulada/métodos , Radioterapia de Intensidade Modulada/efeitos adversos , Feminino , Masculino , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/terapia , Neoplasias Pulmonares/radioterapia , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/mortalidade , Idoso , Pessoa de Meia-Idade , Hospitalização/estatística & dados numéricos , Terapia com Prótons/métodos , Terapia com Prótons/efeitos adversos , Quimiorradioterapia/métodos , Quimiorradioterapia/efeitos adversos , Estudos Retrospectivos , Inibidores de Checkpoint Imunológico/uso terapêutico , Inibidores de Checkpoint Imunológico/efeitos adversos , Linfopenia/etiologia , Anticorpos MonoclonaisRESUMO
Hole transporting layers (HTLs), strategically positioned between electrode and light absorber, play a pivotal role in shaping charge extraction and transport in organic solar cells (OSCs). However, the commonly used poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) HTL, with its hygroscopic and acidic nature, undermines the operational durability of OSC devices. Herein, an environmentally friendly approach is developed utilizing nickel acetate tetrahydrate (NiAc·4H2O) and [2-(9H-carbazol-9-yl)ethyl] phosphonic acid (2PACz) as the NiAc·4H2O/2PACz HTL, aiming at overcoming the limitations posed by the conventional PEDOT:PSS one. Encouragingly, a remarkable power conversion efficiency (PCE) of 19.12% is obtained for the OSCs employing NiAc·4H2O/2PACz as the HTL, surpassing that of devices with the PEDOT:PSS HTL (17.59%), which is ranked among the highest ones of OSCs. This improvement is attributed to the appropriate work function, enhanced hole mobility, facilitated exciton dissociation efficiency, and lower recombination loss of NiAc·4H2O/2PACz-based devices. Furthermore, the NiAc·4H2O/2PACz-based OSCs exhibit superior operational stability compared to their PEDOT:PSS-based counterparts. Of significant note, the NiAc·4H2O/2PACz HTL demonstrates a broad generality, boosting the PCE of the PM6:PY-IT and PM6:Y6-based OSCs from 16.47% and 16.79% (with PEDOT:PSS-based analogs as HTLs) to 17.36% and 17.57%, respectively. These findings underscore the substantial potential of the NiAc·4H2O/2PACz HTL in advancing OSCs, offering improved performance and stability, thereby opening avenue for highly efficient and reliable solar energy harvesting technologies.
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As a common pathological hallmark, protein aggregation into amyloids is a highly complicated phenomenon, attracting extensive research interest for elucidating its structural details and formation mechanisms. Membrane deposition and disulfide-driven protein misfolding play critical roles in amyloid-type aggregation, yet the underlying molecular process remains unclear. Here, we employed sum frequency generation (SFG) vibrational spectroscopy to comprehensively investigate the remodeling process of lysozyme, as the model protein, into amyloid-type aggregates at the cell membrane interface. It was discovered that disulfide reduction concurrently induced the transition of membrane-bound lysozyme from predominantly α-helical to antiparallel ß-sheet structures, under a mode switch of membrane interaction from electrostatic to hydrophobic, and subsequent oligomeric aggregation. These findings shed light on the systematic understanding of dynamic molecular mechanisms underlying membrane-interactive amyloid oligomer formation.
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Amiloide , Dissulfetos , Interações Hidrofóbicas e Hidrofílicas , Muramidase , Dissulfetos/química , Muramidase/química , Muramidase/metabolismo , Amiloide/química , Agregados Proteicos , Animais , Eletricidade EstáticaRESUMO
Silica or calcium fluoride (CaF2) substrate-supported poly(methyl methacrylate) (PMMA) thin films as insulating layers are commonly used in photoelectric/photovoltaic devices to improve the efficiency or stability of these devices. However, a comparative investigation of molecular structures at buried PMMA/silica and PMMA/CaF2 interfaces under thermal stimuli remains unexplored. In this study, we qualitatively and quantitatively revealed different molecular orderings and orientations of PMMA at two interfaces before and after annealing using sum frequency generation (SFG) vibrational spectroscopy. SFG vibrations were carefully assigned by using various deuterated PMMAs. SFG results indicated that, at the buried PMMA/silica interface, the side OCH3 groups were prone to lie down before annealing and tended to stand up after annealing. In contrast, the case was the opposite at the buried PMMA/CaF2 interface. The relative hydrophobicity/hydrophilicity of the two substrates and the developed hydrogen bonds upon annealing at the buried PMMA/silica interface, which is absent at the CaF2 surface, are believed to be the driving forces for different interfacial molecular structures. This study benefits the molecular-level understanding of the interfacial local structural relaxation of polymers at buried interfaces and the rational design of photoelectric/photovoltaic devices from the molecular level.
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This study aimed to evaluate the effects of miR-22 on myocardial fibrosis in rats with myocardial infarction (MI) and to further explore the possible underlying mechanism. A total of 80 rats were randomly divided into Sham group, miR-22 overexpression group, MI group or MI + miR-22 overexpression group. Reverse transcription-polymerase chain reaction (RT-PCR) results showed that compared with Sham group, miR-22 expression level in myocardial tissues of rats decreased significantly in MI group. Overexpression of miR-22 could remarkably relieve cardiac insufficiency in MI rats, increase EF% and FS%, and reduce collagen deposition and the mRNA expression level of fibrosis-promoting genes in myocardial tissues of MI rats. The cross-sectional area of myocardial cells in MI + miR-22 mimic group was smaller than that in MI group. According to the results of immunohistochemical staining, overexpression of miR-22 notably reduced the level of oxidative stress marker 4-HNE in myocardial tissues of MI rats. Meanwhile, myocardial cells in MI + miR-22 mimic group exhibited a prominently lower apoptosis rate than those in MI group. Furthermore, Western blotting results demonstrated that overexpression of miR-22 inhibited the activation of the phosphatase and tensin homolog deleted on chromosome ten (PTEN)/Akt/mTOR signaling pathway in myocardial tissues of MI rats. The inhibitory effects of miR-22 on myocardial fibrosis and hypertrophy after MI in rats may be related to its inhibition on the PTEN/Akt/mTOR signaling pathway. All our findings suggested that miR-22 is expected to become a targeted drug for the clinical treatment of MI.
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Cardiomiopatias , MicroRNAs , Infarto do Miocárdio , Ratos , Animais , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos Sprague-Dawley , MicroRNAs/metabolismo , Transdução de Sinais , Infarto do Miocárdio/genética , Serina-Treonina Quinases TOR/metabolismo , Fibrose , Apoptose/genéticaRESUMO
Nonylphenol (4-NP) has significant adverse effects on the male reproductive system. 4-NP is commonly used in agriculture as a plasticizer and pesticide emulsifier. In the current study, two soil samples with different textures were collected to evaluate the impact of soil components on the environmental existence of 4-NP among soil aggregates. It was found that the presence of soil POM resulted in 4-NP exhibiting a significantly polarized distribution in soil aggregates, instead of the expected increase in content with decreasing particle size. High levels of organic matter and metal oxides result in a high carrying capacity of small aggregates for 4-NP in both soil textures, while POM results in a higher carrying capacity of large aggregates for 4-NP in clay soil. Another important finding is that the existence of 4-NP in soil was regulated by the percentage of aggregates. The results of contribution shown that although small aggregates in sand presented stronger 4-NP carrying capacity, whereas 4-NP was mainly distributed in large aggregates in sand. For clay soil, 4-NP was predominantly located in small aggregates with the 4-NP contributions of small aggregates amounting to 63.17%, despite the highest carrying capacity of 4-NP was observed in large aggregates. These results provide a theoretical basis to investigate the transport and transformation of 4-NP in the soil environment.
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Fenóis , Poluentes do Solo , Solo , Solo/química , Poluentes do Solo/análise , Fenóis/análise , Tamanho da Partícula , Monitoramento AmbientalRESUMO
Within cell plasma membranes, unsaturated lipids are asymmetrically distributed over the inner and outer leaflets, offering an attractive local structural feature. However, the mechanism to keep lipid transmembrane asymmetry and the closely related transmembrane movement (flip-flop) for unsaturated lipids remain poorly understood. Here, we applied sum frequency generation vibrational spectroscopy to investigate this lipid transmembrane asymmetry upon mimicking the cell membrane homeostatic processes. On the one hand, unsaturated lipids were found to hinder the flip-flop process and preserve lipid transmembrane asymmetry in model cell membranes, owing to the steric hindrance caused by their bent tails. On the other hand, local unsaturated lipids in the mixed unsaturated/saturated lipid bilayer were conducive to the formation of the local asymmetry. Therefore, lipid unsaturation can be recognized as an intrinsic key factor to form and maintain lipid transmembrane asymmetry in cell membranes.
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Membrana Celular , Bicamadas Lipídicas , Bicamadas Lipídicas/química , Membrana Celular/química , Membrana Celular/metabolismo , Lipídeos de Membrana/químicaRESUMO
Sympathetic activation is a hallmark of heart failure and the underlying mechanism remains elusive. Butyrate is generated by gut microbiota and influences numerous physiological and pathological processes in the host. The present study aims to investigate whether the intestinal metabolite butyrate reduces sympathetic activation in rats with heart failure (HF) and the underlying mechanisms involved. Sprague-Dawley rats (220â250â g) are anaesthetized with isoflurane, and the left anterior descending artery is ligated to model HF. Then, the rats are treated with or without butyrate sodium (NaB, a donor of butyrate, 10â g/L in water) for 8 weeks. Blood pressure and renal sympathetic nerve activity (RSNA) are recorded to assess sympathetic outflow. Cardiac function is improved (mean ejection fraction, 22.6%±4.8% vs 38.3%±5.3%; P<0.05), and sympathetic activation is decreased (RSNA, 36.3%±7.9% vs 23.9%±7.6%; P<0.05) in HF rats treated with NaB compared with untreated HF rats. The plasma and cerebrospinal fluid levels of norepinephrine are decreased in HF rats treated with NaB. The infusion of N-methyl-D-aspartic acid (NMDA) into the paraventricular nucleus (PVN) of the hypothalamus of HF model rats increases sympathetic nervous activity by upregulating the NMDA receptor. Microglia polarized to the M2 phenotype and inflammation are markedly attenuated in the PVN of HF model rats after NaB administration. In addition, HF model rats treated with NaB exhibit enhanced intestinal barrier function and increased levels of GPR109A, zona occludens-1 and occludin, but decreased levels of lipopolysaccharide-binding protein and zonulin. In conclusion, butyrate attenuates sympathetic activation and improves cardiac function in rats with HF. The improvements in intestinal barrier function, reductions in microglia-mediated inflammation and decreases in NMDA receptor 1 expression in the PVN are all due to the protective effects of NaB.
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Objective: To explore the recovery effect of acupuncture combined with rehabilitation therapy on muscle spasms in patients with spinal cord injury through a systematic review of meta-analysis methods. Methods: Use "acupuncture," "electronic-acupuncture," "spinal cord," "spasm," and "paraplegia" as keywords, CNKI, Google, Wanfang, VIP, sci-hub, Web of Science, PubMed, and other Chinese or English databases were searched. To collect the domestic and foreign research on acupuncture combined with rehabilitation for muscle spasms in patients with spinal cord injury. Preliminary screening was conducted, and data extraction and quality evaluation were carried out on the included literature, including publication time, sample size, treatment methods, recovery effects, etc. According to the literature, the influence of acupuncture combined with rehabilitation therapy on muscle spasms in patients with spinal cord injury and related indices was analyzed. The search period was from January 2018 to June 2023, and the selected research results were tested by RevMan5.3 software and data consolidation for consistency. The methodological quality of the included studies was assessed using the Newcastle-Ottawa Scale (NOS). Results: A preliminary literature search yielded 172 papers. 53 papers from sci-hub, 71 papers from HowNet, 36 papers from Wanfang, and 12 papers from VIP. Finally, 10 articles that met the criteria were included, including 594 patients. According to different treatment methods, the literature about acupuncture combined with rehabilitation therapy for muscle spasms in patients with spinal cord injury was analyzed for consistency, and data were merged. It was concluded that acupuncture combined with rehabilitation The clinical curative effect of the experimental group of patients is higher than that of the control group MD=5.31, 95%CI (2.94, 7.81), Z=5.64, P < .001; the clinical effective rate of the experimental group is higher than that of the control group. The improvement of the clinical spasticity index (CSI) score index of the patients in the experimental group was better than that of the control group MD = -3.09, 95%CI (-4.51, -1.67), Z =4.28, P < .001; the MAS score of the patients in the experimental group The improvement was better than that of the control group MD =-0.76, 95%CI (-1.16, -0.38), Z=8.13, P < .001; the improvement of Barthel index (BI) in the experimental group was better than that of the control group MD=9.81, 95%CI (7.84,11.71), Z=12.71, P < .001; no adverse events were reported in the experimental group and the control group. Conclusion: This study shows that acupuncture and rehabilitation are more effective than other therapeutic methods in the treatment of muscle spasms after spinal cord injury, and more randomized controlled trials are needed to verify this in the future.
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Dissolved organic matter (DOM) is a crucial component of natural sediments that alters Cd sequestration. Nevertheless, how different types of DOM fuel Cd mobilization in Mn-rich sediments has not been elucidated. In the present study, four typical DOM, fluvic acid (FA), bovine serum albumin (BSA), sodium alginate (SA), and sodium dodecyl benzene sulfonate (SDBS), were used to amend Cd-contaminated sediment to study their effects on Cd/Mn biotransformation and microbial community response. The results demonstrated that different DOM drive microbial community shifts and enhance microbially mediated Mn oxide (MnO) reduction and Cd release. The amendment of terrestrial- and anthropogenic-derived DOM (FA and SDBS) mainly contributed to enriching Mn-reducing bacteria phylum Proteobacteria, and its abundance increased by 38.16-74.47 % and 56.41-73.98 %, respectively. Meanwhile, microbial-derived DOM (BSA and SA) mainly stimulated the abundances of metal(loid)-resistant bacteria phylum Firmicutes. Accompanied by microbial community structure, diversity, and co-occurrence network shifts, the DOM concentration and oxidation-reduction potential changed, resulting in enhanced Cd mobilization. Importantly, FA stimulated Cd release most remarkably, probably because of the decreased cooperative interactions between bacterial populations, stronger reduction of MnOs, and higher aromaticity and hydrophobicity of the sediment DOM after amendment. This study linked DOM types to functional microbial communities, and explored the potential roles of different DOM types in Cd biotransformation in lake sediments.
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Cádmio , Manganês , Cádmio/metabolismo , Manganês/metabolismo , Matéria Orgânica Dissolvida , Bactérias/metabolismo , FirmicutesRESUMO
Trueperella pyogenes is an important opportunistic pathogenic bacterium widely distributed in the environment. Pyolysin (PLO) is a primary virulence factor of T. pyogenes and capable of lysing many different cells. PLO is a member of the cholesterol-dependent cytolysin (CDC) family of which the primary structure only presents a low level of homology with other members from 31% to 45%. By deeply studying PLO, we can understand the overall pathogenic mechanism of CDC family proteins. This study established a mouse muscle tissue model infected with recombinant PLO (rPLO) and its single-point mutations, rPLO N139K and rPLO F240A, and explored its mechanism of causing inflammatory damage. The inflammatory injury abilities of rPLO N139K and rPLO F240A are significantly reduced compared to rPLO. This study elaborated on the inflammatory mechanism of PLO by examining its unit point mutations in detail. Our data also provide a theoretical basis and practical significance for future research on toxins and bacteria.
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Proteínas de Bactérias , Proteínas Hemolisinas , Proteína 3 que Contém Domínio de Pirina da Família NLR , Mutação Puntual , Animais , Camundongos , Proteínas Hemolisinas/metabolismo , Proteínas Hemolisinas/genética , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Inflamação/metabolismo , Inflamação/genética , Potássio/metabolismo , Transdução de Sinais , Toxinas Bacterianas/metabolismo , Toxinas Bacterianas/genética , Inflamassomos/metabolismo , HumanosRESUMO
The ecological security pattern can harmonize the relationship between natural environmental protection and socio-economic development. This study proposes a regional ecological security pattern optimization framework by integrating theory and practice with landslide sensitivity and landscape structure. Using Yan'an City as an example, this study optimizes the landscape layout of preliminary ecological sources. The landslide sensitivity index is generated using the information value model and then used to adjust the ecological resistance surface. The Minimum Cumulative Resistance (MCR) approach is used to extract ecological corridors, locate ecological nodes utilizing circuit theory, and outline crucial ecological control areas. The results demonstrate: (1) the ecological sources are primarily composed of forestlands, with a total area of 2,352.2400 km2, concentrated in the southwest, central, and southeast regions. The optimal landscape granularity for the source patches is 600 m. (2) Yan'an is divided into four landslide sensitivity level zones: extremely high, high, medium, and low, with the overall landslide sensitivity of the region being high. (3) The highest ecological resistance is observed in built-up land and the lowest in forestland. The total number of ecological corridors is 26, avoiding most of the highly sensitive areas of landslides. (4) The number of ecological pinch points is 61, while the ecological barrier points amounted to 54. The critical ecological control areas consist mainly of cropland, forestland, and grassland, and differentiated restoration strategies are proposed to address their unique characteristics. The findings of the research can offer scientific guidance for the practice of ecological security protection in geohazard-prone areas.
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Conservação dos Recursos Naturais , Deslizamentos de Terra , China , Conservação dos Recursos Naturais/métodos , Ecologia , Ecossistema , Cidades , FlorestasRESUMO
Sulfur autotrophic denitrification (SAD) occurs without organic carbon sources, offering advantages in removing nitrogen pollutants from water with low carbon to nitrogen ratio. However, ensuring nitrate-reducing sulfide-oxidizing bacteria ability to access the necessary sulfur and inorganic carbon sources is a challenge. Therefore, this study investigated the feasibility of utilizing a SAD composite filler to mitigate nitrogen and phosphorus pollutants concentrations in secondary effluent of wastewater treatment plants (WWTPs) and reduce eutrophication risk in the receiving water. The use of paraffin optimized composite filler with a satisfying 3.70 % break rate and wear rate without dramatically deteriorating contaminant removal performance. The process achieved 94.26 % total nitrogen (TN) and 90.91 % PO43--P removal rates in treating synthetic wastewater; and 2.72 ± 1.92 mg/L and 0.29 ± 0.06 mg/L of TN and PO43--P discharge in treating WWTPs secondary effluent, respectively. The results indicated that denitrification performance of the filler was primarily influenced by variations in NH4+-N resulting from SAD and dissimilatory nitrate reduction to ammonia caused by differences in filler composition and preparation factors. Based on the performance difference in SAD, Fex + leached by H+ in the filler changed, affecting phosphorus removal performance. The change in mechanical properties of the filler was primarily dependent on the surface characteristics of the filler and the content/type of the binder. This study demonstrates the feasibility of using SAD for advanced nitrogen and phosphorus removal from wastewater and applying sulfur/siderite integrated composite filler as a pilot, thereby offering insights for the preparation of SAD fillers.
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This paper develops a thermodynamic entropy-based life prediction model to estimate the low-cycle fatigue (LCF) life of the nickel-based superalloy GH4169 at elevated temperature (650 °C). The gauge section of the specimen was chosen as the thermodynamic system for modeling entropy generation within the framework of the Chaboche viscoplasticity constitutive theory. Furthermore, an explicitly numerical integration algorithm was compiled to calculate the cyclic stress-strain responses and thermodynamic entropy generation for establishing the framework for fatigue life assessment. A thermodynamic entropy-based life prediction model is proposed with a damage parameter based on entropy generation considering the influence of loading ratio. Fatigue lives for GH4169 at 650 °C under various loading conditions were estimated utilizing the proposed model, and the results showed good consistency with the experimental results. Finally, compared to the existing classical models, such as Manson-Coffin, Ostergren, Walker strain, and SWT, the thermodynamic entropy-based life prediction model provided significantly better life prediction results.
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Two-dimensional (2D) antiferromagnetic semiconductor chromium thiophosphate (CrPS4) has gradually become a major candidate material for low-dimensional nanoelectromechanical devices due to its remarkable structural, photoelectric characteristics and potentially magnetic properties. Here, we report the experimental study of a new few-layer CrPS4 nanomechanical resonator demonstrating excellent vibration characteristics through the laser interferometry system, including the uniqueness of resonant mode, the ability to work at the very high frequency, and gate tuning. In addition, we demonstrate that the magnetic phase transition of CrPS4 strips can be effectively detected by temperature-regulated resonant frequencies, which proves the coupling between magnetic phase and mechanical vibration. We believe that our findings will promote the further research and applications of the resonator for 2D magnetic materials in the field of optical/mechanical signal sensing and precision measurement.
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Bolometers based on graphene have demonstrated outstanding performance with high sensitivity and short response time. In situ adjustment of bolometers is very important in various applications, but it is still difficult to implement in many systems. Here we propose a gate-tunable bolometer based on two strongly coupled graphene nanomechanical resonators. Both resonators are exposed to the same light field, and we can measure the properties of one bolometer by directly tracking the resonance frequency shifts, and indirectly measure the other bolometer through mechanical coupling. We find that the sensitivity and the response bandwidth of both bolometers can be independently adjusted by tuning the corresponding gate voltages. Moreover, the properties of the indirectly measured bolometer show a dependence on the coupling between the two resonators, with other parameters being fixed. Our method has the potential to optimize the design of large-scale bolometer arrays, and open new horizons in infrared/terahertz astronomy and communication systems.
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Using metals as signal magnified substrates, surface plasmon-enhanced sum frequency generation (SFG) vibrational spectroscopy is a promising technique to probe weak molecular-level signals at surfaces and interfaces. In this study, the vibrational signals of the n-alkane monolayer on the gold (Au) and silica substrates are investigated using the broadband femtosecond SFG. The enhancement factors are discovered to be up to â¼1076 and â¼31 for the methyl symmetric and asymmetric stretching (ss and as) modes of the monolayer, respectively. By systematically analyzing the second-order nonlinear susceptibility tensor components (χijks), the Fresnel coefficients (Fijks), and the surface plasmon resonance (SPR) effect, we find that the interplay between Fijk and χijk terms and the SPR effect dominate the SFG signal enhancement. Our study reveals that the relative contributions of different influencing factors (i.e., Fresnel coefficients and SPR) to the SFG signal enhancement provide an approach to interpreting enhanced SFG vibrational signals detected from probe molecules on distinct substrates and may finally guide the design of the experimental methodology to improve the detection sensitivity and signal-to-noise ratio.
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Given the ubiquitous detection of antibiotics and antibiotic resistance genes (ARGs) in waterbodies worldwide and increasing public attention to water resource safety, this study investigated the presence of antibiotics and ARGs in the water sources of the Wuhan stretch of the Yangtze River (YR) as well as potential ecological risks. In this study, 15 antibiotics and 10 ARGs in a source of drinking water were analyzed using solid-phase extraction-ultra performance liquid chromatography-mass spectrometry technology (SPE-UPLC-MS/MS) and real-time fluorescence quantitative polymerase chain reaction (qPCR). Fourteen antibiotics were detected in the samples from 18 water sources, with the highest concentration detected for tetracycline, reaching up to 1708.33 ng/L. The detection rates of norfloxacin, enrofloxacin, ofloxacin, tetracycline, and roxithromycin were 100%. The concentrations of antibiotics were highest in She Shui, followed by the Wuhan stretch of the lower reaches of the YR, whereas the lowest concentrations were found in the Wuhan stretch of the upper reaches of the YR which were approximately equal to those in the Han River (HR). Ofloxacin and roxithromycin presented a substantial threat to aquatic organisms with high sensitivity at the majority of the sampling sites. The overall abundance of ARGs was notably greater in the lower reaches of the YR compared with the upper reaches and the HR. The highest absolute abundance was observed for sulfa ARGs. Integron intl1 strongly correlated with sul1, sul2, ermB, and qnrS, and antibiotics, strongly correlated with multiple ARGs, suggesting that antibiotics and ARGs are present in water sources in Wuhan and may present a plausible hazard to both human and ecological well-being. Hence, regulating the spread and dissemination of antibiotics and ARGs in the environment is imperative. The findings of this research offer significant insights into the stewardship and safeguarding of aquatic reserves in the Wuhan stretch of the YR.