RESUMO
The designed synthesis of a crystalline azulene-based covalent organic framework (COF-Azu-TP) is presented and its photothermal property is investigated. Azulene, a distinctive 5-7 fused ring non-benzenoid aromatic compound with a large intramolecular dipole moment and unique photophysical characteristics, is introduced as the key feature in COF-Azu-TP. The incorporation of azulene moiety imparts COF-Azu-TP with broad-spectrum light absorption capability and interlayer dipole interactions, which makes COF-Azu-TP a highly efficient photothermal conversion material. Its polyurethane (PU) composite exhibits a solar-to-vapor conversion efficiency (97.2%) and displays a water evaporation rate (1.43 kg m-2 h-1) under one sun irradiation, even at a very low dosage of COF-Azu-TP (2.2 wt%). Furthermore, COF-Azu-TP is utilized as a filler in a polylactic acid (PLA)/polycaprolactone (PCL) composited shape memory material, enabling rapid shape recovery under laser stimulation. A comparison study with a naphthalene-based COF isomer further emphasizes the crucial role of azulene in enhancing photothermal conversion efficiency. This study demonstrates the significance of incorporating specific building blocks into COFs for the development of functional porous materials with enhanced properties, paving the way for future applications in diverse fields.
RESUMO
Covalent organic frameworks (COFs) have been demonstrated as promising photocatalysts for hydrogen peroxide (H2O2) production. However, the construction of COFs with new active sites, high photoactivity, and wide-range light absorption for efficient H2O2 production remains challenging. Herein, we present the synthesis of a novel azobenzene-bridged 2D COF (COF-TPT-Azo) with excellent performance on photocatalytic H2O2 production under alkaline conditions. Notably, although COF-TPT-Azo differs by only one atom (-N=N- vs. -C=N-) from its corresponding imine-linked counterpart (COF-TPT-TPA), the COF-TPT-Azo exhibits a significantly narrower band gap, enhanced charge transport, and prompted photoactivity. Remarkably, when employed as a metal-free photocatalyst, COF-TPT-Azo achieves a high photocatalytic H2O2 production rate up to 1498 µmol g-1 h-1 at pH =11, which is 7.9 times higher than that of COF-TPT-TPA. Further density functional theory (DFT) calculations reveal that the -N=N- linkages are the active sites for photocatalysis. This work provides new prospects for developing high-performance COF-based photocatalysts.
RESUMO
Covalent organic frameworks (COFs) have emerged as a new class of cathode materials for energy storage in recent years. However, they are limited to two-dimensional (2D) or three-dimensional (3D) framework structures. Herein, this work reports designed synthesis of a redox-active one-dimensional (1D) COF and its composites with 1D carbon nanotubes (CNTs) via in situ growth. Used as cathode materials for Li-ion batteries, the 1D COF@CNT composites with unique dendritic core-shell structure can provide abundant and easily accessible redox-active sites, which contribute to improve diffusion rate of lithium ions and the corresponding specific capacity. This synergistic structural design enables excellent electrochemical performance of the cathodes, giving rise to 95% utilization of redox-active sites, high rate capability (81% capacity retention at 10 C), and long cycling stability (86% retention after 600 cycles at 5 C). As the first example to explore the application of 1D COFs in the field of energy storage, this study demonstrates the great potential of this novel type of linear crystalline porous polymers in battery technologies.
RESUMO
Boron-based covalent organic frameworks (COFs) are susceptible to nucleophilic attack by water at the electron-deficient boron sites and even slightly humid air could destroy the integrity of their porous frameworks within hours. Such instability is a major limitation to the practical applications of boron-based COFs. Herein we report a significant enhancement of hydrostability of boroxine-linked COFs (COF-1 as representative) by modification with an oligoamine (tetraethylenepentamine, TEPA), which leads to survival of the modified COF in water and long-time stability under humid atmosphere. Meanwhile, the TEPA modification also results in a considerable increase in CO2 adsorption capacity up to 13â times and a dramatic improvement in CO2 /N2 selectivity in low pressure region, which make the modified COF suitable for capturing CO2 from flue gas. This work provides a facile, efficient, and scalable method to greatly improve hydrostability of boroxine-linked COFs and reshape them into high-performance CO2 adsorbents.
RESUMO
Lithium-sulfur (Li-S) batteries are a promising energy storage technology due to their tempting high theoretical capacity and energy density. Nevertheless, the wastage of active materials that originates from the shuttling effect of polysulfides still hinders advancement of Li-S batteries. The effective design of cathode materials is extremely pivotal to solve this thorny problem. Herein, surface engineering in covalent organic polymers (COPs) has been performed to investigate the influence of pore wall polarity on the performance of COP-based cathodes used for Li-S batteries. With the assistance of experimental investigation and theoretical calculations, performance improvement by increasing pore surface polarity and a synergy effect of the polarized functionalities, along with nano-confinement effect of the COPs, are disclosed, to which the improved performance of Li-S batteries including outstanding Coulombic efficiency (99.0 %) and extremely low capacity decay (0.08 % over 425 cycles at 1.0â C) is attributed. This work not only enlightens the designable synthesis and applications of covalent polymers as polar sulfur hosts with high utilization of active materials, but also provides a feasible guide for the design of effective cathode materials for future advanced Li-S batteries.
RESUMO
PURPOSE: To determine the risk factors for postoperative fever after retrograde intrarenal surgery (RIRS) in patients with negative preoperative urine culture (UC), and to establish a nomogram for predicting postoperative fever based on these risk factors. METHODS: This study collected 322 patients with negative UC who received RIRS at the First Affiliated Hospital of Anhui Medical University from March 2019 to May 2022. The study population was divided into a fever group and a non-fever group. The risk factors of postoperative fever were determined by univariate and multivariate logistic regression analyses, and a nomogram was established. The nomogram was evaluated in terms of differentiation, calibration, and clinical practicability. RESULTS: In this study, 47 (14.6%) patients developed a fever after surgery. Multivariate logistic regression analysis showed that for patients with negative preoperative urine culture, urinary leucocyte esterase (P = 0.005), operative time (P = 0.019), and intraoperative hypotension (P = 0.028) were independent risk factors of postoperative fever, and a nomogram was constructed according to the above variables. The area under the curve (AUC) calculated by receiver operating characteristic (ROC) analysis was 0.807 (95% CI 0.739-0.876), indicating good discrimination. The calibration curves showed good consistency, and the clinical decision curve analysis (DCA) showed the clinical applicability of the model. CONCLUSIONS: For patients with negative preoperative urine culture, urine leukocyte esterase, operative time, and intraoperative hypotension are independent risk factors of postoperative fever. The new nomogram can better assess the risk of infection in patients with negative UC after RIRS.
Assuntos
Hipotensão , Nomogramas , Humanos , Febre/epidemiologia , Febre/etiologia , Urinálise , Fatores de Risco , Estudos RetrospectivosRESUMO
Oily water caused in the process of industry leads to not only the waste of resources, but also environmental pollution. Membrane separation, as a facile and efficient separation technology, has attracted widespread attention in the field of oil/water separation. The development of membrane materials with high separation performance is one of the key elements to improve separation efficiency. In this work, a superhydrophobic membrane composited with a trifluoromethyl-containing covalent organic framework (COF) is prepared, which exhibits excellent performance on separations of oil/water mixtures and water-in-oil emulsions. For different composition of oil/water mixtures, the highest flux of oil is up to 32 000 L m-2 h-1 and oil/water separation efficiency is above 99%. Moreover, the high oil/water separation efficiency remains unchanged after successive cycles. This work provides a feasible scheme for the design of high-efficiency oil/water separation membranes.
Assuntos
Estruturas Metalorgânicas , Membranas , Poluição Ambiental , Tecnologia , Interações Hidrofóbicas e HidrofílicasRESUMO
Ion-containing polymers play a critical role in various energy and sensing applications. Adjusting ionic solvation is one approach to tune the performance of ion-containing polymers. Small zwitterionic molecule additives have presented their ability to regulate ionic solvation because they possess two charged groups covalently connected together. One remaining question is how the effect of zwitterionic molecules on ionic solvation depends on their own chemical structures, especially the anionic groups. To shed light on this question, we investigate the ionic solvation structure and dynamics in LiTFSI/(ethylene oxide)10 (EO10) with the presence of three distinct zwitterionic molecules (MPC, SB, and CB) using molecular dynamics simulations (MPC: 2-methacryloyloxyethyl phosphorylcholine, SB: sulfobetaine ethylimidazole, CB: carboxybetaine ethylimidazole, and LiTFSI: lithium bis(trifluoromethylsulfonyl)-imide). The simulation systems include two Li+ : O(EO10) molar ratios: 1 : 6 and 1 : 18. The simulation results show that all three zwitterionic molecules reduce the Li+-EO10 coordination number in the order of MPC > CB > SB. In addition, nearly 10% of Li+ exclusively coordinates with MPC molecules, only 2-4% of Li+ exclusively cooridinates with CB molecules, while no Li+ exclusively coordinates with SB molecules. MPC molecules also present the most stable Li+ coordination among the three zwitterionic molecules. Our simulations indicate that zwitterionic molecule additives may benefit a high Li+ concentration environment. At a low Li+ concentration, all three zwitterionic molecules reduce the diffusion coefficient of Li+. However, at a high Li+ concentration, only SB molecules reduce the diffusion coefficient of Li+.
RESUMO
BACKGROUND: Finding some convenient and economical indicators to initially screen overweight and obese patients at high risk of kidney stone recurrence can help them prevent stone recurrence with lower medical cost. The purpose of this article is to determine the clinical value of Ae index (Apo B × 1000/eGFR) as an independent predictor for kidney stone recurrence in overweight and obese populations. METHODS: We queried the electronic medical records of patients with kidney stone operated at our hospital from March 2016 to March 2022, and selected BMI ≥ 25 kg/m2 as the study population and divided the patients into stone recurrence group and non-recurrence group. Relevant parameters of routine blood and biochemical test, glycated serum protein (GSP), and history of hypertension and hyperglycemia were collected. Then the Chi-square test, independent samples t-test or Wilcoxon rank-sum test were used to calculate the differences between the two groups of data. Next, we performed univariate and multivariate logistic regression analysis to screen out the most significant variables Apo B and eGFR, and then we calculated the Ae index using the formula Apo B × 1000/eGFR, and analyzed the relationship between Ae index and kidney stone recurrence. RESULTS: Univariate analysis found that Apo B (OR:8.376,95%CI:3.093-22.680), Creatinine (OR:1.012,95%CI:1.003-1.021), Cystatin C(OR:2.747,95%CI:1.369-5.508), LDL-C (OR:1.588,95%CI:1.182-2.134), TC (OR:1.543,95%CI:1.198-1.988) were positively associated, eGFR (OR:0.980,95%CI:0.970-0.991) was negatively associated with kidney stone recurrence. And multivariate logistic regression analysis suggested that Apo B (OR:11.028, 95%CI:3.917-31.047) and eGFR (OR:0.976, 95%CI:0.965-0.988) were the most significant factors. Then we calculated Ae index and analyzed it, the sensitivity was 74.26% and the specificity was 60.00%, higher than either individual variable. Its smoothed curve revealed a non-linear relationship between them with the inflection point of 9.16. And the OR on the left side of the inflection point was 1.574 (95% CI: 1.228-2.018), whereas the OR on the right side of the inflection point was 1.088 (95% CI: 1.007-1.177). CONCLUSIONS: Ae index is an easily calculated and obtained index that has some predictive value for kidney stone recurrence in overweight and obese patients, which is of interest.
Assuntos
Cálculos Renais , Sobrepeso , Humanos , Sobrepeso/complicações , Obesidade/complicações , Cálculos Renais/etiologia , Apolipoproteínas B , CreatininaRESUMO
Flexible covalent organic frameworks (COFs) are intriguing for their dynamic properties distinctive from rigid counterparts but still suffer from limited accessibility. Especially, controlling flexibility of COFs is challenging and the impact of different flexibility on properties of COFs has rarely been unveiled. This article reports stepwise adjustment on flexibility of two-dimensional COFs, which is realized by the designed synthesis of rigid COF (R-COF), semi-flexible COF (SF-COF), and flexible COF (F-COF) through polymerization, linker exchange, and linkage conversion with a newly developed method for reduction of hydrazone, respectively. Significant difference in breathing behavior and self-adaptive capability of the three COFs are uncovered through vapor response and iodine capture experiments. Gas sorption experiments indicate that the porosity of F-COF could switch from "close" state in nitrogen to "open" state in carbon dioxide, which are not observed for R-COF and SF-COF. This study not only develops a strategy to adjust the flexibility of COFs by tuning their linkers and linkages, but also provides a deep insight into the impact of different flexibility on properties of COFs, which lays a foundation for the development of this new class of dynamic porous materials.
RESUMO
Amide-linked covalent organic frameworks (amide COFs) possess enormous potentials in practical applications benefiting from their high stability and polyamide structures. However, they suffer from very limited accessibility. Herein, we report a new linkage conversion method to rapidly synthesize crystalline amide COFs through oxidation of imine linkages in their corresponding imine-linked frameworks with KHSO5 as an oxidant under very mild conditions. This synthetic strategy is general, facile, efficient, and scalable, as demonstrated by the procedure of simply stirring mixtures of imine-linked COFs (seven examples) and KHSO5 in anhydrous dimethylformamide for several hours to complete the conversions and gram-scale synthesis. The high efficiency of this approach enables facile production of amide COFs from widely available imine-linked COFs, which lays the foundation for exploring practical applications of this unique type of polyamide material.
RESUMO
BACKGROUND AND AIMS: Natural killer (NK) cells play an important role in biliary atresia (BA) pathogenesis; human poliovirus receptor (PVR) is an important NK-cell modulator. Here, we explored the role of PVR in BA pathogenesis. METHODS: Poliovirus receptor expression and NK cell-associated genes were detected in human BA samples and a rotavirus-induced BA mouse model using quantitative PCR and immunofluorescence staining. Chemically modified small interfering RNA silenced PVR expression in the BA model, and its effects on the population and function of intrahepatic NK cells were investigated using flow cytometry (FCM). The effects of PVR overexpression and knockdown on proliferation, apoptosis and NK-cell-mediated lysis of cultured human cholangiocytes were analysed using FCM and cell viability assays. Serum PVR, high-mobility group box 1 (HMGB1), and interleukin-1beta (IL-1beta) levels were measured in a cohort of 50 patients using ELISA. RESULTS: Poliovirus receptor expression was upregulated in the biliary epithelium of BA patients and BA model and was positively correlated with the population and activation of intrahepatic NK cells. Silencing of PVR expression impaired the cytotoxicity of NK cells, reduced inflammation and protected mice from rotavirus-induced BA. Activation of the TLR3-IRF3 signalling pathway induced PVR expression in cultured cholangiocytes. PVR overexpression promoted proliferation and inhibited the apoptosis of cholangiocytes but exacerbated NK cell-mediated cholangiocyte lysis. Serum PVR levels were elevated in BA patients and were positively correlated with HMGB1 and IL-1beta levels. CONCLUSIONS: Poliovirus receptor contributes to BA pathogenesis by regulating NK cell-mediated bile duct injury; PVR has the value as a biomarker of BA.
Assuntos
Atresia Biliar , Proteína HMGB1 , Rotavirus , Humanos , Camundongos , Animais , Atresia Biliar/etiologia , Atresia Biliar/metabolismo , Atresia Biliar/patologia , Proteína HMGB1/metabolismo , Células Matadoras Naturais , Ductos Biliares/patologiaRESUMO
Accurate control of the layer number of orderly stacked 2D polymers has been an unsettled challenge in self-assembly. Herein we describe the fabrication of a bilayer 2D supramolecular organic framework from a monolayer 2D supramolecular organic framework in water by utilizing the cooperative coordination of a rod-like bipyridine ligands to zinc porphyrin subunits of the monolayer network. The monolayer supramolecular framework is prepared from the co-assembly of an octacationic zinc porphyrin monomer and cucurbit[8]uril (CB[8]) in water through CB[8]-encapsulation-promoted dimerization of 4-phenylpyridiunium subunits that the zinc porphyrin monomer bear. The bilayer 2D supramolecular organic framework exhibits structural regularity in both solution and the solid state, which is characterized by synchrotron small-angle X-ray scattering and high-resolution transmission electron microscopic techniques. Atomic force microscopic imaging confirms that the bilayer character of the 2D supramolecular organic framework can be realized selectively on the micrometer scale.
RESUMO
Covalent organic frameworks (COFs) are an emerging class of crystalline porous organic polymers with potential for innovative applications. Here we report the use of COFs as precursors for the fabrication of well-defined tubular nanomaterials. A proof-of-concept study is presented for the controllable fabrication of organic nanotubes through selective disassembly of two-dimensional heteropore COFs. Two dual-pore COFs are constructed based on orthogonal reactions. Each COF possesses two different kinds of pores, which are formed by linking all-hydrzaone-bonded nanopores with boroxines. Selectively hydrolyzing boroxine rings in the COFs while keeping hydrazone linkages untouched gives rise to organic nanotubes with diameters and shapes corresponding to the nanochannels of the COFs.
RESUMO
Fungal growth-dependent gene coregulation is strongly implicated in alteration of gene-encoding target proteases ruling with an antifungal resistance niche and biology of resistant mutants. On the basis of multi-alterative processes in this platform, the resistance-modifying strategy is designed in ketoconazole resistant Candida albicans and evaluated with less selective Momordica charantia protein and allosterically phosphorylated derivatives at the Thr102, Thr24 and Thr255 sites, respectively. We demonstrate absolutely chemo-sensitizing efficacy regarding stepwise-modifying resistance in sensitivity, by a load of only 26.23-40.00 µg/l agents in Sabouraud's dextrose broth. Five successive modifying-steps realize the decreasing of ketoconazole E-test MIC50 from 11.10 to a lower level than 0.10 mg/l. With the ketoconazole resistance-modifying, colony undergoes a high-frequency morphological switch between high ploidy (opaque) and small budding haploid (white). A cellular event in the first modifying-step associates with relatively slow exponential growth (ie, a 4-h delay)-dependent action, mediated by agents adsorption. Moreover, multiple molecular roles are coupled with intracellularly and extracellularly binding to ATP-dependent RNA helicase dbp6; the 0.08-2.45 fold upregulation of TATA-box-binding protein, rRNA-processing protein and translation initiation factor 5A; and the 7.52-55.33% decrease of cytochrome P450 lanosterol 14α-demethylase, glucan 1, 3-ß glucosidase, candidapepsin-1 and 1-acylglycerol-3-phosphate O-acyltransferase. Spatial and temporal gene coregulation, in the transcription and translation initiation stages with rRNA-processing, is a new coprocessing platform enabling target protease attenuations for resistance-impairing. An updated resistance-modifying measure of these agents in the low-dose antifungal strategic design may provide opportunities to a virtually safe therapy that is in high dose-dependency. LAY SUMMARY: A new platform to modify resistance is fungal growth-dependent gene coregulation. MAP30 and phosphorylated derivatives are candidate resistance-modifying agents. Low-dose stepwise treatment absolutely modifies azole resistance in model fungus.
RESUMO
As a new woody oleaginous crop, tree peony is now being widely developed and utilized, which attributed to the outstanding oil-use features regarding the fatty acid profiles and bioactivity. The major fatty acid profiles and bioactivity of seed oils in ten tree peony varieties collected from a common garden were investigated in the present study. The results showed that the oil yields, fatty acid profiles, bioactivity of seed oils existed significant variations among ten tree peony varieties (P<0.05). Considered the application value, 'Fengdan' (FD) and 'Ziban' (ZB) was the optimal resources as the high oil yields, rich unsaturated fatty acids especially high α-linolenic acid of 40.46 %, great antioxidant activity with low IC50 values, high ABTS and FRAP values, and strong antimicrobial activity with high DIZ and low MIC/MBC values. The study also confirmed seed oil of tree peony as the potential raw materials sources in functional food, pharmaceuticals and cosmetics for human health.
Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Antioxidantes/farmacologia , Cosméticos/química , Ácidos Graxos/farmacologia , Paeonia/química , Antibacterianos/química , Antifúngicos/química , Antioxidantes/química , Bactérias/efeitos dos fármacos , Benzotiazóis/antagonistas & inibidores , Ácidos Graxos/química , Recuperação de Fluorescência Após Fotodegradação , Fungos/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Óleos de Plantas/química , Sementes/química , Ácidos Sulfônicos/antagonistas & inibidores , Árvores/químicaRESUMO
New linkage chemistry will endow covalent organic frameworks (COFs) with not only structural diversity but also fascinating properties. However, to develop a new type of linkages has been a great challenge. We herein report the first two COFs using aminal as the linkages. These two COFs have been synthesized by condensation of secondary amine and aldehyde. They crystallize in cpi net, which is a new topology for COFs. The aminal linkage is found to favor reservation of photophysical property of the monomers due to its tetrahedral geometry and nonconjugated feature. These aminal-COFs exhibit good thermal stability and high chemical stability under neutral and basic conditions.
RESUMO
Covalent organic frameworks (COFs) are an emerging class of crystalline porous organic materials which are fabricated via reticular chemistry. Their topologic structures can be precisely predicted on the basis of the structures of building blocks. However, constructing COFs with complicated structures has remained a great challenge, due to the limited strategies that can access to the structural complexity of COFs. In this work, we have developed a new approach to produce COFs bearing three different kinds of pores. The design is fulfilled by the combination of vertex-truncation with multiple-linking-site strategy. On the basis of this design, a "V"-shaped building block carrying two aldehyde groups on the end of each branch has been synthesized. Condensation of it with 1,4-diaminobenzene or benzidine leads to the formation of two triple-pore COFs, TP-COF-DAB and TP-COF-BZ, respectively. The topological structures of the triple-pore COFs have been confirmed by PXRD studies, synchrotron small-angle X-ray scattering (SAXS) experiments, theoretical simulations, and pore size distribution analyses. Furthermore, for the first time, an in situ COF-to-COF transformation has also been achieved by heating TP-COF-BZ with 1,4-diaminobenzene under solvothermal condition, which leads to the formation of TP-COF-DAB via in situ replacing the benzidine linkers in TP-COF-BZ with 1,4-diaminobenzene linkers.
RESUMO
Interlayer stacking of 2D covalent organic frameworks (COFs) plays a crucial role in determining not only the geometry of channels inside COFs but also the mobility of carrier transport between COF layers. However, though topological structures of 2D COFs monolayers can be precisely predicted through the structures of building blocks, factors affecting their interlayer stacking remain poorly understood. In this work, a truxene-based building block on which six methyl groups are introduced was designed. The condensation of it with 1,4-diaminobenzene or benzidine afforded 2D COFs with the methyl groups extending out-of-plane of the layers. A significant influence of the methyl groups on interlayer stacking of the COFs was revealed by the adoption of inclined packing of monolayers, which has never been experimentally observed before. This unprecedented stacking manner was confirmed by powder X-ray diffraction analysis, pore-size distribution analysis, and TEM investigation.
RESUMO
CONTEXT: Naringin is a natural flavanone glycoside that is found in the Chinese herbal medicines and citrus fruits. Studies have demonstrated that naringin possesses numerous biological and pharmacological properties, but few reviews of these studies have been performed. OBJECTIVE: The present review gathers the fragmented information available in the literature describing the extraction of naringin, its pharmacology and its controlled release formulations. Current research progress and the therapeutic potential of naringin are also discussed. METHODS: A literature survey for relevant information regarding the biological and pharmacological properties of naringin was conducted using Pubmed, Sciencedirect, MEDLINE, Springerlink and Google Scholar electronic databases from the year 2007-2015. RESULTS: Naringin modulates signalling pathways and interacts with signalling molecules and thus has a wide range of pharmacological activities, including anti-inflammatory, anti-cancer activities, as well as effects on bone regeneration, metabolic syndrome, oxidative stress, genetic damage and central nervous system (CNS) diseases. Information was gathered that showed the extraction of naringin can be improved using several modifications. There has been some progress in the development of controlled release formulations of naringin. CONCLUSION: Naringin is a promising candidate for further in vivo studies and clinical use. More detailed studies regarding its mechanism of action are required.