RESUMEN
Metal organic frameworks are an attractive platform to develop fascinating electrocatalysts for the oxidation of ascorbic acid (AA), and their different morphologies have been hinted in literature to impact their sensing performance. In this work, by varying the reaction medium of metal source and organic ligand, copper 2-hydroxybenzene-1,4-dicarboxylate (CuBDC-OH) nanosheets (NSs), nanorods (NRs) and bulk were generated. Thereinto, CuBDC-OH-NSs displayed the highest sensitivity of 151.99µA mM-1cm-2in the linear range of 12-1074µM, which is 1.5 times greater than that of CuBDC-OH NRs and 3.5 times greater than that of CuBDC-OH bulk. The electrochemical analyzes manifested that the superiority of nanosheets originated from higher oxidative current, larger electrochemical active surface area and lower charge transfer resistance, which enabling the efficient electro-oxidation of AA. Additionally, satisfactory selectivity, stability and reproducibility were obtained.
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Small and homogeneously dispersed Au and Pt nanoparticles (NPs) were prepared on polymeric carbon nitride (CNx )/mesoporous silica (SBA-15) composites, which were synthesized by thermal polycondensation of dicyandiamide-impregnated preformed SBA-15. By changing the condensation temperature, the degree of condensation and the loading of CNx can be controlled to give adjustable particle sizes of the Pt and Au NPs subsequently formed on the composites. In contrast to the pure SBA-15 support, coating of SBA-15 with polymeric CNx resulted in much smaller and better-dispersed metal NPs. Furthermore, under catalytic conditions the CNx coating helps to stabilize the metal NPs. However, metal NPs on CNx /SBA-15 can show very different catalytic behaviors in, for example, the CO oxidation reaction. Whereas the Pt NPs already show full CO conversion at 160 °C, the catalytic activity of Au NPs seems to be inhibited by the CNx support.
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Oro/química , Nanopartículas del Metal/química , Nanopartículas/química , Nitrilos/química , Platino (Metal)/química , Polímeros/química , Silicatos/química , Dióxido de Silicio/química , Catálisis , Oxidación-ReducciónRESUMEN
BACKGROUND: To investigate whether intravenous administration of tranexamic acid (TXA) prior to arthroscopic rotator cuff repair improves operative blood loss, postoperative fibrinolytic index, inflammatory response, and postoperative pain. METHODS: This was a prospective, double-blind, randomized controlled study. From January 2023 to February 2024, 64 patients who required arthroscopic rotator cuff repair were included and divided into tranexamic acid group (T group) group and control group (C group) according to the random number table method. In T group, 1000 mg TXA was administered intravenously 10 minutes before surgery, and an equivalent dose of normal saline was administered intravenously 10 minutes before surgery in C group. Intraoperative bleeding, postoperative fibrinolytic indexes, inflammatory indexes, pain scores, and occurrence of adverse effects were compared between the 2 groups. RESULTS: Intraoperative bleeding in T group was lower than that in C group (Pâ <â .05); D-D and FDP in T group were significantly lower than those in C group (Pâ <â .05); postoperative TNF-α and IL-6 in 2 groups was higher than that before operation and T group was lower than C group (Pâ <â .05); The pain scores of the 2 groups after operation were lower than those before operation (Pâ <â .05), and there was no difference between the 2 groups (Pâ >â .05). CONCLUSION SUBSECTIONS: TXA is able to reduce blood loss and inflammatory reactions, modulate fibrinolytic function, and promote postoperative recovery in patients undergoing arthroscopic rotator cuff repair, with no elevated risk of complications.
Asunto(s)
Antifibrinolíticos , Artroscopía , Pérdida de Sangre Quirúrgica , Dolor Postoperatorio , Lesiones del Manguito de los Rotadores , Ácido Tranexámico , Humanos , Ácido Tranexámico/uso terapéutico , Ácido Tranexámico/administración & dosificación , Masculino , Femenino , Antifibrinolíticos/uso terapéutico , Antifibrinolíticos/administración & dosificación , Método Doble Ciego , Persona de Mediana Edad , Artroscopía/métodos , Artroscopía/efectos adversos , Estudios Prospectivos , Lesiones del Manguito de los Rotadores/cirugía , Pérdida de Sangre Quirúrgica/prevención & control , Dolor Postoperatorio/tratamiento farmacológico , Anciano , Adulto , Administración IntravenosaRESUMEN
Growing three-dimensional (3D) metal organic frameworks (MOFs) via heterogeneous epitaxial growth on metal hydroxide arrays are effective for constructing electrochemical sensor. However, the growth of MOFs is difficult to control, resulting in thick and irregular morphologies and even damage the metal hydroxide template. In this work, Cu3(HHTP)2 (HHTP = 2, 3, 6, 7, 10, 11-hexahydroxytriphenylene) films with controllable thickness and morphology were successfully prepared on Cu(OH)2 nanowire arrays (NWAs) through layer-by-layer (LBL) growth method. We have discovered that the LBL cycle and the reaction solvent composition are crucial for growing homogenous MOF thin films. The Cu3(HHTP)2 based ascorbic acid (AA) sensor, fabricated in ethanol within 10 LBL cycles, generated an ultrahigh sensitivity of 821.64 µA mM-1 cm-2 in the range of 6-981.41 µM, a low detection limit of 60 nM as well as the great selectivity, stability and reproducibility. Moreover, the relative deviation for AA detection in two fruit juices were 3.22 % and 3.71 %, and the test result for human sweat fall within the normal AA concentration range, verifying the feasibility of as-prepared sensor for practical application.
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Técnicas Biosensibles , Estructuras Metalorgánicas , Nanocables , Humanos , Reproducibilidad de los Resultados , Ácido Ascórbico , HidróxidosRESUMEN
This study combined inorganic α-hemihydrate gypsum (α-HHG) with organic polyacrylamide (PAM) hydrogel to create a novel α-HHG/PAM composite material. Through this facile composite strategy, this fabricated material exhibited a significantly longer initial setting time and higher mechanical strength compared to α-HHG. The effects of the addition amount and the concentration of PAM precursor solution on the flowability of the α-HHG/PAM composite material slurry, initial setting time, and mechanical properties of the hardened specimens were investigated. The structural characteristics of the composite material were examined using XRD, FE-SEM, and TGA. The results showed that the initial setting time of the α-HHG/PAM composite material was 25.7 min, which is an extension of 127.43% compared to that of α-HHG. The flexural strength and compressive strength of the oven-dried specimens were 23.4 MPa and 58.6 MPa, respectively, representing increases of 34.73% and 84.86% over values for α-HHG. The XRD, FE-SEM, and TGA results all indicated that the hydration of α-HHG in the composite material was incomplete. The incompleteness is caused by the competition between the hydration process of inorganic α-HHG and the gelation process of the acrylamide molecules for water, which hinders some α-HHG from entirely reacting with water. The enhanced mechanical strength of the α-HHG/PAM composite material results from the tight interweaving and integrating of organic and inorganic networks. This study provides a concise and efficient approach to the modification research of hemihydrate gypsum.
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Architecture design is widely regarded as a rational strategy to enhance the sensing performance of electrocatalysts. Herein, the novel three-dimensional hybrids based on Au and Cu2O were successfully synthesized via steps of in-situ growth, including anodic oxidation, annealing and galvanic displacement. Cu2O appeared in the morphology of nanowire array on conductive substrate, and was decorated by Au nanoparticles. Benefiting from the unique architecture and binder-free fabrication process, the Au/Cu2O nanowire arrays possessed high conductivity and abundant exposed active sites, as well as facilitated the direct electron transfer among detection object, electrocatalyst and current collector. Moreover, Au/Cu2O particles as contrast were fabricated to clarify the effect of structure on sensing ability. The Au/Cu2O nanowire arrays drove the glucose electro-oxidation reaction with great catalytic activity, in which a potential as low as 0.4 V was needed to reach a high sensitivity of 2.098 mA mM-1 cm-2. The excellent selectivity, stability and reproducibility were also obtained by the sensor. Furthermore, the quantitative detection of glucose level in diluted human serum were performed and the satisfactory result make the obtained sensor have the potential for practical applications.
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Técnicas Biosensibles , Nanopartículas del Metal , Nanocables , Humanos , Nanocables/química , Reproducibilidad de los Resultados , Oro/química , Nanopartículas del Metal/química , Cobre/química , Técnicas Biosensibles/métodos , Técnicas Electroquímicas , GlucosaRESUMEN
Noninvasive human health monitoring requires the development of efficient electrochemical sensors for the quantitative analysis of infinitesimal biomolecules. In this work, we reported a novel hierarchical nanosheet assemblies (HSA) of copper-based metal-organic frameworks (MOFs) as an electrochemical sensor for ascorbic acid (AA) detection. Copper 1,4-benzenedicarboxylate (CuBDC) HSA was constructed by three steps of in situ growth on stone paper, including hydrolysis, anion exchange, and heteroepitaxy growth. The monodispersed two-dimensional MOFs nanosheet units were aligned in an orderly manner and arranged into three-dimensional hierarchical assemblies. The CuBDC HSA-based AA sensor displayed a high sensitivity of 396.8 µA mM-1 cm-2 and a low detection limit of 0.1 µM. Excellent selectivity, stability and reproducibility were also obtained. Benefiting from the advantages of ultrathin nanosheets and nature-inspired hierarchy, this unique architecture facilitated reactant dispersion and maximized the accessible active sites and charge-transport capability and thus had superior catalytic ability for the electro-oxidation of ascorbic acid compared to bulk MOFs. Moreover, the CuBDC HSA sensor performed AA level detection in juice samples with acceptable accuracy and verified the feasibility for sweat AA sensing. This novel MOFs architecture holds great potential as an electrochemical sensor to detect AA for noninvasive human health monitoring in the future.
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Cobre , Estructuras Metalorgánicas , Humanos , Cobre/química , Estructuras Metalorgánicas/química , Ácido Ascórbico/análisis , Reproducibilidad de los Resultados , Técnicas Electroquímicas/métodosRESUMEN
In this study, lychee-like TiO2@Fe2O3 microspheres with a core-shell structure have been prepared by coating Fe2O3 on the surface of TiO2 mesoporous microspheres using the homogeneous precipitation method. The structural and micromorphological characterization of TiO2@Fe2O3 microspheres has been carried out using XRD, FE-SEM, and Raman, and the results show that hematite Fe2O3 particles (7.05% of the total mass) are uniformly coated on the surface of anatase TiO2 microspheres, and the specific surface area of this material is 14.72 m2 g-1. The electrochemical performance test results show that after 200 cycles at 0.2 C current density, the specific capacity of TiO2@Fe2O3 anode material increases by 219.3% compared with anatase TiO2, reaching 591.5 mAh g-1; after 500 cycles at 2 C current density, the discharge specific capacity of TiO2@Fe2O3 reaches 273.1 mAh g-1, and its discharge specific capacity, cycle stability, and multiplicity performance are superior to those of commercial graphite. In comparison with anatase TiO2 and hematite Fe2O3, TiO2@Fe2O3 has higher conductivity and lithium-ion diffusion rate, thereby enhancing its rate performance. The electron density of states (DOS) of TiO2@Fe2O3 shows its metallic nature by DFT calculations, revealing the essential reason for the high electronic conductivity of TiO2@Fe2O3. This study presents a novel strategy for identifying suitable anode materials for commercial lithium-ion batteries.
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Graphitic carbon nitride (g-C3N4) nanosheets have been successfully immobilized on diatomite to form a g-C3N4/diatomite hybrid through a facile electrostatic adsorption method and subsequent calcination process. Electron microscopy studies confirm that the surface of the diatomite is tightly covered with g-C3N4 nanosheets. In addition, the characterization results of Fourier transform infrared spectra (FTIR) and X-ray photoelectron spectra (XPS) verify that there is a strong interaction between the g-C3N4 and diatomite components inside the hybrids. The visible light absorption edge of the hybrids exhibits a significant redshift compared with the bare g-C3N4 nanosheets and diatomite, which leads to the improvement of visible light absorption and utilization. The photocatalytic results demonstrated that the photocatalytic performance for methyl orange and phenol degradation using the hybrids as photocatalysts has been obviously improved compared to that of g-C3N4 nanosheets, which may be ascribed to its adsorption/photocatalysis synergistic effect.
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ZnO powders with various size scales (mean diameter size: 10, 50, 200 and 1000nm) have been prepared by two different preparation methods, thermal evaporation method and chemical deposition method, and examined as photocatalysts for the UV-induced degradation of methyl orange in water solution. ZnO nanoparticle with diameter size 50nm prepared by thermal evaporation method showed the highest photocatalytic activity. In addition, the tetrapod ZnO nanopowders had the higher efficiency than irregular ZnO particles. However, the smallest 10nm ZnO nanoparticle prepared by chemical deposition method indicated the lower efficiency contrast to 200nm ZnO powders prepared by thermal evaporation method. The results indicated preparation method was the decisive factor rather than size and morphology. Moreover, the effect of catalyst loading, pH value and the initial dye concentration on the final degradation efficiency were discussed through the photocatalytic experiments using 50nm ZnO nanoparticle as photocatalyst.
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Compuestos Azo/química , Compuestos Azo/efectos de la radiación , Colorantes/química , Colorantes/efectos de la radiación , Óxido de Zinc/química , Catálisis , Concentración de Iones de Hidrógeno , Nanopartículas , Tamaño de la Partícula , Fotoquímica , Rayos Ultravioleta , Eliminación de Residuos Líquidos/métodos , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/efectos de la radiación , Purificación del Agua/métodosRESUMEN
ZnO complex nanostructure with special mushroom-like morphology was prepared by hydrolysis of zinc acetate dehydrate (Zn(CH3COO)2 2H2O) in water-methanol mixed solvent at 60 degrees C. The formation mechanism was studied using XRD investigation and FE-SEM observation, which showed that the mushroom-like particles were transformed from cauliflower-like layered basic zinc acetate (LBZA), Zn5(OH)8(CH3COO)22H2O, and composed of ZnO subunits with average size less than 10 nm. The introduction of hexamethylenetetramine (HMTA, C6H12N4) to the solution before deposition led to drastic changes in the morphologies of both aggregation particles and ZnO subunits. The novel ZnO microspheres, which were made of regular hexagonal plate-like ZnO with dimensional size 35 x 10 nm, were formed. These hexagonal plate-like ZnO subunits stacked very compactly and aligned regularly. Kinetic study of this unique complex nanostructure using TEM and FE-SEM observation showed the presence of HMTA played an important role on the formation of hexagonal ZnO subunits through different mechanisms related to the different parts of microspheres.
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The photodegradation of methylene blue in aqueous solutions is studied using various photocatalysts, including neat TiO(2), CNT-TiO(2), Au-TiO(2), and Au-CNT-TiO(2) composites MB. Materials were synthesized and extensively characterized by XRD, TEM, DRFIT spectroscopy, N(2) adsorption-desorption isotherms, as well as diffuse reflectance UV-vis spectroscopy. By using CNT-TiO(2) composite as catalysts, it was found that CNT act as adsorbent and photosensitizer to improve the photoactivity of neat TiO(2). Among the CNT-TiO(2) composites with different CNT weight ratio (0.2-20%), the 2%CNT-TiO(2) shows the best photoactivity. When CNT content is larger than 2%, the surplus CNT may absorb and scatter light photons. Combined with the decrease of TiO(2) amount in composite, the photoactivity is reduced. To further improve the photoactivity of 2%CNT-TiO(2), different Au loads varying from 0.25% to 1% were introduced by the deposition-precipitation method. The 0.25%Au-2%CNT-TiO(2) composite had the highest photoactivity. The increase in activity was explained by the surface plasmon resonance of Au that makes the composite to absorb more photons than the 2%CNT-TiO(2), thus overcoming the disadvantages of surplus CNT addition. On the other hand, 0.25%Au-2%CNT-TiO(2) composite also presents higher activity than 0.25%Au-TiO(2) due to higher adsorption capacity provided by CNT introduction. The addition of CNT and Au simultaneously has a much stronger synergic role than when each of them is introduced individually.
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Oro/química , Azul de Metileno/química , Nanotubos de Carbono/química , Titanio/química , Contaminantes Químicos del Agua/química , Adsorción , Catálisis , Azul de Metileno/efectos de la radiación , Fotólisis , Eliminación de Residuos Líquidos/métodos , Contaminantes Químicos del Agua/efectos de la radiación , Purificación del Agua/métodosRESUMEN
Highly oriented Ga-doped zinc oxide (ZnO) nanorod arrays have been prepared on a ZnO-buffered silicon substrate in an aqueous solution, which is a mixture of methenamine (C(6)H(12)N(4)), zinc nitrate hexahydrate (Zn(NO(3))(2)·6H(2)O), and gallium nitrate hydrate (Ga(NO(3))(3)·xH(2)O). The microstructure characteristics and optical properties of the nanorod arrays were analyzed using different characterization techniques including field-emission scanning electron microscopy (FESEM), x-ray photoelectron spectroscopy (XPS), and photoluminescence (PL). The experimental results show that the morphology, density, and surface compositions of ZnO nanorod arrays are sensitive to the concentration of gallium nitrate hydrate. The PL spectra of all ZnO nanorod arrays show three different emissions, including UV (ultraviolet), yellow, and NIR (near infrared) emissions. With the increase in the Ga doping level, the luminescence quality of ZnO nanorods has been improved. The peak of UV emission has a small redshift, which can be ascribed to the combined effect of size and Ga doping. Furthermore, Ga doping has caused defects that respond to NIR emission.