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The secondary structures of polypeptides, such as an α-helix and a ß-sheet, often impart specific properties and functions, making the regulation of their secondary structures of great significance. Particularly, water-soluble polypeptides bearing a ß-sheet conformation are rare and challenging to achieve. Here, a series of oligo(ethylene glycol)-modified lysine N-carboxylic anhydrides (EGmK-NCA, where m = 1-3) and the corresponding polymers EGmKn are synthesized, with urethane bonds as the linker between the side-chain EG and lysine. The secondary structure of EGmKn is delicately regulated by both m and n, the length (number of repeating units) of EG and the degree of polymerization (DP), respectively. Among them, EG2Kn adopts a ß-sheet conformation with good water solubility at an appropriate DP and forms physically cross-linked hydrogels at a concentration as low as 1 wt %. The secondary structures of EG1Kn can be tuned by DP, exhibiting either a ß-sheet or an α-helix, whereas EG3Kn appears to a adopt pure and stable α-helix with no dependence on DP. Compared to previous works reporting EG-modified lysine-derived polypeptides bearing exclusively an α-helix conformation, this work highlights the important and unexpected role of the urethane connecting unit and provides useful case studies for understanding the secondary structure of polypeptides.
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Peptídeos , Conformação Proteica em Folha beta , Solubilidade , Água , Peptídeos/química , Água/química , Polietilenoglicóis/química , Lisina/química , Hidrogéis/química , Etilenoglicol/química , Estrutura Secundária de Proteína , PolimerizaçãoRESUMO
Arbuscular mycorrhizal (AM) fungi-associated hyphosphere microbiomes can be considered as the second genome of the mycorrhizal phosphorus uptake pathway. Their composition can be thought of as a stably recurring component of a holobiont, defined by the hyphosphere core microbiome, which is thought to benefit AM fungal fitness. Here, we review evidence indicating the existence of the hyphosphere core microbiome, highlight its functions linked to those functions lacking in AM fungi, and further explore the mechanisms by which different core members ensure their stable coexistence. We conclude that deciphering and utilizing the hyphosphere core microbiome provides an entry point for understanding the complex interactions among plants, AM fungi, and bacteria.
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The mycorrhizal pathway is an important phosphorus (P) uptake pathway for more than two-thirds of land plants. The arbuscular mycorrhizal (AM) fungi-associated hyphosphere microbiome has been considered as the second genome of mycorrhizal P uptake pathway and functionality in mobilizing soil organic P (Po). However, whether there is a core microbiome in the hyphosphere and how this is implicated in mining soil Po are less understood. We established on-site field trials located in humid, semiarid, and arid zones and a microcosm experiment in a glasshouse with specific AM fungi and varying soil types to answer the above questions. The hyphosphere microbiome of AM fungi enhanced soil phosphatase activity and promoted Po mineralization in all sites. Although the assemblage of hyphosphere microbiomes identified in three climate zones was mediated by environmental factors, we detected a core set in three sites and the subsequent microcosm experiment. The core members were co-enriched in the hyphosphere and dominated by Alphaproteobacteria, Actinobacteria, and Gammaproteobacteria. Moreover, these core bacterial members aggregate into stable guilds that contributed to phosphatase activity. The core hyphosphere microbiome is taxonomically conserved and provides functions, with respect to the mineralization of Po, that AM fungi lack.
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Microbiota , Micorrizas , Micorrizas/metabolismo , Fósforo/metabolismo , Fungos/metabolismo , Bactérias/metabolismo , Solo , Microbiologia do Solo , Monoéster Fosfórico Hidrolases/metabolismo , Raízes de Plantas/metabolismoRESUMO
BACKGROUND: To study the effects of quercetin on the functionality of myofibrillar proteins (MPs), various levels of quercetin (0, 10, 50, 100 and 200 µmol g-1 protein) were added to MP solution and the structure and gel properties of MPs were determined. RESULTS: Compared with the control MPs not treated with quercetin, adding 10, 50 and 100 µmol g-1 quercetin caused a significant (P < 0.05) loss of sulfhydryls; 10 and 50 µmol g-1 quercetin enhanced the surface hydrophobicity significantly (P < 0.05), and 50, 100 and 200 µmol g-1 quercetin reduced the fluorescence intensity of tryptophan. Additions of 50, 100 and 200 µmol g-1 quercetin resulted in a significant (P < 0.05) reduction in MP solubility. Adding 10, 50 and 100 µmol g-1 quercetin did not significantly (P > 0.05) change the gel strength and water-holding ability of MPs than control, but 200 µmol g-1 quercetin declined the gel properties significantly (P < 0.05). The microstructure and dynamic rheological properties confirmed the results of the gel properties of MPs affected by various levels of quercetin. CONCLUSION: The results obtained in the present study show that mildly high levels of quercetin can maintain the gel properties of MPs, which may be a result of the moderate MP cross-linkage and aggregation caused by the covalent and non-covalent interactions of MPs. © 2023 Society of Chemical Industry.
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Carne de Porco , Carne Vermelha , Animais , Suínos , Quercetina/análise , Proteínas Musculares/química , Carne Vermelha/análise , Miofibrilas/química , Conformação Proteica , Géis/químicaRESUMO
Pancreatic lipase (PL) is a well-known key target for the prevention and treatment of obesity. Human carboxylesterase 1A (hCES1A) has become an important target for the treatment of hyperlipidaemia. Thus, the discovery of potent dual-target inhibitors based on PL and hCES1A hold great potential for the development of remedies for treating related metabolic diseases. In this study, a series of natural triterpenoids were collected and the inhibitory effects of these triterpenoids on PL and hCES1A were determined using fluorescence-based biochemical assays. It was found that oleanolic acid (OA) and ursolic acid (UA) have the excellent inhibitory effects against PL and hCES1A, and highly selectivity over hCES2A. Subsequently, a number of compounds based on the OA and UA skeletons were synthesised and evaluated. Structure-activity relationship (SAR) analysis of these compounds revealed that the acetyl group at the C-3 site of UA (compound 41) was very essential for both PL and hCES1A inhibition, with IC50 of 0.75 µM and 0.014 µM, respectively. In addition, compound 39 with 2-enol and 3-ketal moiety of OA also has strong inhibitory effects against both PL and hCES1A, with IC50 of 2.13 µM and 0.055 µM, respectively. Furthermore, compound 39 and 41 exhibited good selectivity over other human serine hydrolases including hCES2A, butyrylcholinesterase (BChE) and dipeptidyl peptidase IV (DPP-IV). Inhibitory kinetics and molecular docking studies demonstrated that both compounds 39 and 41 were effective mixed inhibitors of PL, while competitive inhibitors of hCES1A. Further investigations demonstrated that both compounds 39 and 41 could inhibit adipocyte adipogenesis induced by mouse preadipocytes. Collectively, we found two triterpenoid derivatives with strong inhibitory ability on both PL and hCES1A, which can be served as promising lead compounds for the development of more potent dual-target inhibitors targeting on PL and hCES1A.
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Hidrolases de Éster Carboxílico/antagonistas & inibidores , Descoberta de Drogas , Inibidores Enzimáticos/farmacologia , Lipase/antagonistas & inibidores , Pâncreas/enzimologia , Triterpenos/farmacologia , Hidrolases de Éster Carboxílico/metabolismo , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Humanos , Lipase/metabolismo , Estrutura Molecular , Relação Estrutura-Atividade , Triterpenos/síntese química , Triterpenos/químicaRESUMO
BACKGROUND: Identifying the interscalene brachial plexus can be challenging during ultrasound-guided interscalene block. OBJECTIVE: We hypothesised that an algorithm based on deep learning could locate the interscalene brachial plexus in ultrasound images better than a nonexpert anaesthesiologist, thus possessing the potential to aid anaesthesiologists. DESIGN: Observational study. SETTING: A tertiary hospital in Shanghai, China. PATIENTS: Patients undergoing elective surgery. INTERVENTIONS: Ultrasound images at the interscalene level were collected from patients. Two independent image datasets were prepared to train and evaluate the deep learning model. Three senior anaesthesiologists who were experts in regional anaesthesia annotated the images. A deep convolutional neural network was developed, trained and optimised to locate the interscalene brachial plexus in the ultrasound images. Expert annotations on the datasets were regarded as an accurate baseline (ground truth). The test dataset was also annotated by five nonexpert anaesthesiologists. MAIN OUTCOME MEASURES: The primary outcome of the research was the distance between the lateral midpoints of the nerve sheath contours of the model predictions and ground truth. RESULTS: The data set was obtained from 1126 patients. The training dataset comprised 11â392 images from 1076 patients. The test dataset constituted 100 images from 50 patients. In the test dataset, the median [IQR] distance between the lateral midpoints of the nerve sheath contours of the model predictions and ground truth was 0.8 [0.4 to 2.9] mm: this was significantly shorter than that between nonexpert predictions and ground truth (3.4âmm [2.1 to 4.5] mm; Pâ<â0.001). CONCLUSION: The proposed model was able to locate the interscalene brachial plexus in ultrasound images more accurately than nonexperts. TRIAL REGISTRATION: ClinicalTrials.gov (https://clinicaltrials.gov) identifier: NCT04183972.
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Bloqueio do Plexo Braquial , Plexo Braquial , Anestésicos Locais , Inteligência Artificial , Plexo Braquial/diagnóstico por imagem , Bloqueio do Plexo Braquial/métodos , China , Humanos , Redes Neurais de Computação , Ultrassonografia de Intervenção/métodosRESUMO
With currently available molecular imaging techniques, hepatocellular carcinoma (HCC), a liver cancer with high mortality rates and poor treatment responses, is mostly diagnosed at its late stage. This is largely due to the lack of highly sensitive contrast agents with high liver specificity. Herein, we report a novel bimodal contrast agent molecule CNCI-1 for the effective detection of HCC at its early stage both in vitro and in vivo. The agent has high liver specificity with effective X-ray computed tomography (CT)/near-infrared (NIR) imaging functions. It has been successfully applied to in vivo NIR imaging with high sensitivity and high selectivity to the HCC region of the HepG2 tumor-xenografted mice model and LM3 orthotopic hepatoma mice model. Moreover, the agent was found to be noninvasive and hepatocarcinoma cells preferential. Furthermore, it also enhanced the tumor imaging by revealing the blood vessels nearby for the CT image acquisition in the VX2 orthotopic hepatoma rabbit model. Our design strategy provides a new avenue to develop the medical relevant bimodal contrast agents for diagnosis of HCC at its early stage.
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Carcinoma Hepatocelular/diagnóstico por imagem , Meios de Contraste/química , Neoplasias Hepáticas/diagnóstico por imagem , Acetanilidas/síntese química , Acetanilidas/química , Acetanilidas/toxicidade , Animais , Carcinoma Hepatocelular/patologia , Meios de Contraste/síntese química , Meios de Contraste/toxicidade , Células Hep G2 , Humanos , Indóis/síntese química , Indóis/química , Indóis/toxicidade , Neoplasias Hepáticas/patologia , Masculino , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Coelhos , Tomografia Computadorizada por Raios XRESUMO
In this study, we observe and study the early evolution of cavitation bubbles generated during pulsed laser ablation of titanium targets in different liquid environments utilizing a high-resolution stroboscopic shadowgraphy system. A hydrodynamic model is proposed to calculate the early pressure changes within the bubble and in the surrounding fluid. Our results show that the cavitation bubble is a low-pressure region that is bounded by a high-pressure fluid lamina after the incipient stage, and its evolution is primarily affected by the liquid density. Moreover, the initial bubble pressure increases substantially in high viscosity liquids. This work illuminates how the liquid properties affect the early bubble dynamics and is a step towards a deeper understanding of laser-materials interactions in liquid environments.
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We report a facile top-flat square nanosecond (ns) laser direct writing ablation technique in a thin silver film substrate to fabricate the silver square-shaped cell structure of flexible transparent electrodes. Square silver cell structures feature smooth surface morphology, excellent edge definition, mechanical stability, strong adhesion to the substrate, and favorable resistance and transparency. In particular, this strategy enables fabrication of a high square-shaped cell areal density (ablated square cell to the total area) Ag mesh, substantially improving transparency ($ {\gt} {85}\% $>85%) without considerably sacrificing conductivity ($ {\lt} {5}\;\Omega \;{{\rm sq}^{ - 1}}$<5Ωsq-1 unit of resistance). Consequently, the proposed metallic square-shaped structure shows compatibility with a polyethylene naphthalate flexible substrate for silver-based wearable electronic devices without any protective layer over the electrodes.
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Laser-induced periodic surface structures (LIPSS) are a universal phenomenon that can allow tailoring nanoelectronics and nanophotonics devices. However, there is an issue about the formation mechanism of LIPSS, and the current research mainly focuses on the formation process of the individual structures, such as the low spatial frequency LIPSS (LSFL), sub-wavelength structures, and laser-induced periodic annular surface structures (LIPASS). A whole process formation picture of the series of these periodic structures is still missing. In this study, a pump-probing setup is applied to ensure the real-time and in situ monitoring of surface modification under different pulse numbers. LSFL firstly appears on the surface after two laser shots, and then, laser-induced orthogonal periodic structures (LIOPS) become the dominant morphology after five laser shots, which result from the local field enhancement of the surface ripples. As the laser shots increase, the LSFL split leads to the formation of nanopillars, and the formation of the nanopillars under the surface LSFL (after ten laser shots) is due to the transition between the LSFL and HSFL with an orientation parallel to the laser polarization. A dip surrounded by annular periodic fringes after 50 laser shots is observed, which is due to the interference of the incident laser field and the reflected laser field on the crater surface. Finally, a direct writing technique for fabrication of nano-gratings is also reported.
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The effects of Al2O3 nanoparticles on the precipitation behavior of CaCO3 and on the anti-scale performance of 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA) in CaCO3 growth solution were studied by means of solution analysis, gravimetric methods, scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The results illustrate that Al2O3 nanoparticles had little effect on the concentration of calcium ions in the test solution without PBTCA, but significantly changed the form and morphology of calcium carbonate crystals, which were transformed from calcite to aragonite. As a commonly used and effective scale inhibitor, PBTCA showed good Ca2+ retention ability in the test solution, distorting the calcite crystal lattice and promoting the formation of vaterite. When Al2O3 nanoparticles co-existed with PBTCA in the test solution, calcium carbonate was more likely to precipitate, and the Ca2+ retention ability of PBTCA reduced. A newly designed gravimetric method was used to evaluate the scale inhibition performance of Al2O3 nanoparticles on the heat exchange surface. When the concentration of Al2O3 nanoparticles reached 1 g/L, the surface scale inhibition efficiency of Al2O3 nanoparticles exceeded 80%.
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Micro-electromechanical (MEM) switches, with advantages such as quasi-zero leakage current, emerge as attractive candidates for overcoming the physical limits of complementary metal-oxide semiconductor (CMOS) devices. To practically integrate MEM switches into CMOS circuits, two major challenges must be addressed: sub 1 V operating voltage to match the voltage levels in current circuit systems and being able to deliver at least millions of operating cycles. However, existing sub 1 V mechanical switches are mostly subject to significant body bias and/or limited lifetimes, thus failing to meet both limitations simultaneously. Here 0.2 V MEM switching devices with â³106 safe operating cycles in ambient air are reported, which achieve the lowest operating voltage in mechanical switches without body bias reported to date. The ultralow operating voltage is mainly enabled by the abrupt phase transition of nanolayered vanadium dioxide (VO2 ) slightly above room temperature. The phase-transition MEM switches open possibilities for sub 1 V hybrid integrated devices/circuits/systems, as well as ultralow power consumption sensors for Internet of Things applications.
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The surface states of brass in simulated cooling water (SCW) containing or free of sodium dodecyl benzene sulfonate (SDBS) and TiO2 nanofluid were analyzed by means of scanning electron microscope (SEM), energy spectrum analysis (EDS) and X-ray diffraction (XRD). The concentrations of Cu and Zn ions in the solution after brass immersion were analyzed using a plasma emission spectrometer. The relationship between the surface states and corrosion resistance of brass was investigated by electrochemical impedance spectroscopy (EIS). The results showed that the brass surface was mainly covered with zinc compound Zn5(OH)6(CO3)2 as corrosion product in SCW. In SCW containing SDBS, a large amount of SDBS was adsorbed on the brass surface. In TiO2 nanofluid, the brass surface was relatively bare and mainly contained cuprous oxide. There was no obvious adhesion of SDBS aggregates and no accumulation of zinc compound on brass surface in TiO2 nanofluid. TiO2 nanoparticles inhibit the adsorption of SDBS on brass surface. Solution analysis results showed that the concentrations of Cu and Zn ions in TiO2 nanofluid was obviously higher than that in SCW and SCW containing SDBS, indicating that most of corrosion products of brass dissolved into the nanofluid. The EIS results illustrated the brass electrode had a larger reaction resistance in SCW containing SDBS, indicating the good protective performance of the adsorbed SDBS film on brass surface. The reaction resistance of the brass electrode was the smallest in TiO2 nanofluid, which illustrated that TiO2 nanoparticles in solution promoted the corrosion of brass.
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The influence of Al2O3 nanoparticles on corrosion inhibition of benzotriazole (BTA) in brass/ simulated water system was studied by potentiodynamic polarization curve and electrochemical impedance spectroscopy (EIS). The results show that BTA has good corrosion inhibition effect on brass. Al2O3 nanoparticles could reduce the corrosion inhibition performance of BTA. The higher the concentration of Al2O3 nanoparticles in simulated water, the lower corrosion inhibition performance of BTA. The isothermal adsorption of BTA on brass surface in simulated water and Al2O3 nanofluids was analyzed. The results indicated that the adsorption of BTA on brass surface followed the Langmuirs' adsorption isotherm, the adsorption Gibbs free energy ΔG was less than -40 kJ/mol, corresponding to chemical adsorption, in both simulated water and Al2O3 nanofluids. The -ΔG value of BTA on brass surface decreased in Al2O3 nanofluids, indicating the weakening of the BTA adsorption on the brass surface. Surface analysis of brass samples by optical microscope and X-ray diffraction confirmed the above results.
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Recent research indicates that the C-terminal Eps15 homology domain 1 is associated with epithelial growth factor receptor-mediated endocytosis recycling in non-small-cell lung cancer. The aim of this study was to determine the clinical significance of Eps15 homology domain 1 gene expression in relation to phosphorylation of epithelial growth factor receptor expression in patients with breast cancer. Primary breast cancer samples from 306 patients were analyzed for Eps15 homology domain 1, RAB11FIP3, and phosphorylation of epithelial growth factor receptor expression via immunohistochemistry. The clinical significance was assessed via a multivariate Cox regression analysis, Kaplan-Meier curves, and the log-rank test. Eps15 homology domain 1 and phosphorylation of epithelial growth factor receptor were upregulated in 60.46% (185/306) and 53.92% (165/306) of tumor tissues, respectively, as assessed by immunohistochemistry. The statistical correlation analysis indicated that Eps15 homology domain 1 overexpression was positively correlated with the increases in phosphorylation of epithelial growth factor receptor ( r = 0.242, p < 0.001) and RAB11FIP3 ( r = 0.165, p = 0.005) expression. The multivariate Cox proportional hazard model analysis demonstrated that the expression of Eps15 homology domain 1 alone is a significant prognostic marker of breast cancer for the overall survival in the total, chemotherapy, and human epidermal growth factor receptor 2 (-) groups. However, the use of combined expression of Eps15 homology domain 1 and phosphorylation of epithelial growth factor receptor markers is more effective for the disease-free survival in the overall population, chemotherapy, and human epidermal growth factor receptor 2 (-) groups. Moreover, the combined markers are also significant prognostic markers of breast cancer in the human epidermal growth factor receptor 2 (+), estrogen receptor (+), and estrogen receptor (-) groups. Eps15 homology domain 1 has a tumor suppressor function, and the combined marker of Eps15 homology domain 1/phosphorylation of epithelial growth factor receptor expression was identified as a better prognostic marker in breast cancer diagnosis. Furthermore, RAB11FIP3 combines with Eps15 homology domain 1 to promote the endocytosis recycling of phosphorylation of epithelial growth factor receptor.
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Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Neoplasias da Mama/metabolismo , Proteínas de Transporte/metabolismo , Receptores ErbB/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Inclusão em ParafinaRESUMO
OBJECTIVE: To investigate the diabetogenic effects of the immunosuppressive agent tacrolimus, the reversibility of these effects upon treatment discontinuation, and the underlying mechanisms in a rat model. MATERIALS AND METHODS: 60 healthy male rats were randomly divided into three groups for intragastric administration of tacrolimus either at 4 mg/kg/d or 2 mg/kg/d or an equal volume of normal saline (control). The treatment was administered for 5 months, followed by a 5-month period of no intervention. Fasting plasma glucose and insulin levels were used to calculate the homeostasis model assessment of ß-cell function (HOMA-ß) and insulin sensitivity index (ISI). RESULTS: Tacrolimus treatment significantly increased blood glucose concentrations (p < 0.05) and lowered HOMA-ß and ISI (p < 0.01) in a time- and dose-dependent manner. Five months after tacrolimus treatment, significant islet cell injury was observed. However, 5 months after tacrolimus discontinuation, blood glucose concentrations significantly declined, HOMA-β and ISI levels significantly increased, and islet cell morphology noticeably improved. CONCLUSIONS: In conclusion, tacrolimus treatment of healthy rats increased blood glucose concentrations in a time- and concentration-dependent manner. Development of tacrolimus-induced diabetes and reversibility after tacrolimus discontinuation may involve factors of and interactions between the insulin secretion pathway, local and/or systemic insulin resistance, and islet cell damage.
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Imunossupressores/toxicidade , Resistência à Insulina , Insulina/metabolismo , Ilhotas Pancreáticas/efeitos dos fármacos , Tacrolimo/toxicidade , Animais , Glicemia/análise , Peso Corporal , Secreção de Insulina , Ilhotas Pancreáticas/patologia , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
The monocyte-to-high-density lipoprotein cholesterol ratio (MHR) is a novel marker that can help estimate the degree of atherosclerosis by considering inflammation and lipid abnormalities. This study aimed to assess the association between the MHR and prevalent heart failure (HF) and to explore the value of the MHR in detecting prevalent HF in the general US population. Our study included 25,374 participants from the National Health and Nutrition Examination Survey (1999-2018). Among the participants, 749 (2.95%) reported a history of HF, and the HF group had a significantly higher MHR than the non-HF group. Adjusted analyses revealed that each standard deviation increase in the MHR was associated with a 27.8% increase in the risk of HF. The association between the MHR and prevalent HF was linear across the entire MHR range. Adding the MHR to conventional cardiovascular risk factors significantly improved the area under the curve (0.875; p < 0.001), continuous net reclassification index (0.187; p < 0.001), and integrated discrimination index (0.004; p < 0.001). Our study suggests a potential association between the MHR and HF risk, and the findings enhance HF risk stratification and provide novel insights into the interplay between the coronary atherosclerotic burden and HF in clinical settings.
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HDL-Colesterol , Insuficiência Cardíaca , Monócitos , Inquéritos Nutricionais , Humanos , Insuficiência Cardíaca/sangue , Insuficiência Cardíaca/epidemiologia , Insuficiência Cardíaca/diagnóstico , Monócitos/metabolismo , Masculino , Feminino , HDL-Colesterol/sangue , Pessoa de Meia-Idade , Idoso , Prevalência , Adulto , Biomarcadores/sangue , Fatores de RiscoRESUMO
Converting CO2 into energy-rich fuels by using solar energy is a sustainable solution that promotes a carbon-neutral economy and mitigates our reliance on fossil fuels. However, affordable and efficient CO2 conversion remains an ongoing challenge. Here, we introduce polymeric g-C3N4 into the pores of a hollow In2O3 microtube. This architecture results in a compact and staggered arrangement between g-C3N4 and In2O3 components with an increased contact interface for improved charge separation. The hollow interior further contributes to strengthening light absorption. The resulting g-C3N4-In2O3 hollow tubes exhibit superior activity (274 µmol·g-1·h-1) toward CO2 to CO conversion in comparison with those of pure In2O3 and g-C3N4 (5.5 and 93.6 µmol·g-1·h-1, respectively), underlining the role of integrating g-C3N4 and In2O3 in this advanced system. This work offers a strategy for the advanced design and preparation of hollow heterostructures for optimizing CO2 adsorption and conversion by integrating inorganic and organic semiconductors.
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BACKGROUND: Fungi and bacteria coexist in a wide variety of environments, and their interactions are now recognized as the norm in most agroecosystems. These microbial communities harbor keystone taxa, which facilitate connectivity between fungal and bacterial communities, influencing their composition and functions. The roots of most plants are associated with arbuscular mycorrhizal (AM) fungi, which develop dense networks of hyphae in the soil. The surface of these hyphae (called the hyphosphere) is the region where multiple interactions with microbial communities can occur, e.g., exchanging or responding to each other's metabolites. However, the presence and importance of keystone taxa in the AM fungal hyphosphere remain largely unknown. RESULTS: Here, we used in vitro and pot cultivation systems of AM fungi to investigate whether certain keystone bacteria were able to shape the microbial communities growing in the hyphosphere and potentially improved the fitness of the AM fungal host. Based on various AM fungi, soil leachates, and synthetic microbial communities, we found that under organic phosphorus (P) conditions, AM fungi could selectively recruit bacteria that enhanced their P nutrition and competed with less P-mobilizing bacteria. Specifically, we observed a privileged interaction between the isolate Streptomyces sp. D1 and AM fungi of the genus Rhizophagus, where (1) the carbon compounds exuded by the fungus were acquired by the bacterium which could mineralize organic P and (2) the in vitro culturable bacterial community residing on the surface of hyphae was in part regulated by Streptomyces sp. D1, primarily by inhibiting the bacteria with weak P-mineralizing ability, thereby enhancing AM fungi to acquire P. CONCLUSIONS: This work highlights the multi-functionality of the keystone bacteria Streptomyces sp. D1 in fungal-bacteria and bacterial-bacterial interactions at the hyphal surface of AM fungi. Video Abstract.
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Hifas , Microbiota , Micorrizas , Raízes de Plantas , Microbiologia do Solo , Streptomyces , Micorrizas/fisiologia , Micorrizas/classificação , Streptomyces/classificação , Streptomyces/isolamento & purificação , Streptomyces/genética , Streptomyces/fisiologia , Hifas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Fósforo/metabolismo , Interações Microbianas/fisiologia , Solo/química , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismoRESUMO
As a remarkable multifunctional material, ferroferric oxide (Fe3O4) exhibits considerable potential for applications in many fields, such as energy storage and conversion technologies. However, the poor electronic and ionic conductivities of classical Fe3O4 restricts its application. To address this challenge, Fe3O4 nanoparticles are combined with graphene oxide (GO) via a typical hydrothermal method, followed by a conductive wrapping using poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic sulfonate) (PEDOT:PSS) for the fabrication of composite films. Upon acid treatment, a highly conductive porous Fe3O4@RGO/PEDOT:PSS hybrid is successfully constructed, and each component exerts its action that effectively facilitates the electron transfer and subsequent performance improvement. Specifically, the Fe3O4@RGO/PEDOT:PSS porous film achieves a high specific capacitance of 244.7 F g-1 at a current of 1 A g-1. Furthermore, due to the facial fabrication of the highly conductive networks, the free-standing film exhibits potential advantages in flexible thermoelectric (TE) materials. Notably, such a hybrid film shows a high electric conductivity (σ) of 507.56 S cm-1, a three times greater value than the Fe3O4@RGO component, and achieves an optimized Seebeck coefficient (S) of 13.29 µV K-1 at room temperature. This work provides a novel route for the synthesis of Fe3O4@RGO/PEDOT:PSS multifunctional films that possess promising applications in energy storage and conversion.