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A triple alkoxo bridged dinuclear cobalt(III) complex mimicking phosphatase and showing ability to degrade organic dye contaminants by photocatalysis
摘要： A dinuclear cobalt(III) complex, [(N3)L1CoIIIL2CoIIIL1] (1), has been synthesized and characterized {H2L1 = 2-((1-hydroxybutan-2-ylimino)methyl)-4-bromophenol and HL2 = 2-amino-1-butanol}. Single crystal X-ray diffraction analysis confirmed its structure. Extended supra-molecular architectures were generated in the complex through weak noncovalent interactions. The energetic features of significant supramolecular interactions have been investigated using DFT calculation and further corroborated with NCI plot index computational tool. The complex has been found to mimic the role of phosphatase enzyme efficiently by transforming 4-nitrophenylphosphate to 4-nitrophenolate at room temperature. The reaction follows Michaelis–Menten enzymatic reaction kinetics with turnover numbers of ~1.4 s-1 in aqueous DMF (98% DMF, v/v) medium. The complex also acts as an efficient photocatalyst for degradation of organic pollutants. Methylene blue (MB), a widely used dye in various industries, was selected as a model pollutant in aqueous media to evaluate the photocatalytic effectiveness of the complex.
关键词： DFT calculation,phosphatase mimicking activity,Photocatalytic degradation of methylene blue (MB),Cobalt(III),Crystal structure
更新于2025-09-23 15:23:52
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One-pot synthesis of visible-light-driven photocatalyst for degradation of Rhodamine B: graphene based bismuth/bismuth(III) oxybromide
摘要： A ternary photocatalyst, graphene based bismuth modified bismuth(III) oxybromide (Bi/BiOBr/G), was synthesized via a facile one-step solvothermal method using only ethylene glycol as both solvent and reducing reagent. Bi/BiOBr/G exhibits higher photocatalytic activity than bismuth(III) oxybromide (BiOBr) on degradation of Rhodamine B under visible-light illumination, and the photodegradation rate is 4.9 times that of BiOBr. The enhanced photocatalytic activity is attributed to the synergistic effect among Bismuth, graphene and BiOBr, which can effectively promote the visible-light absorption of Bi/BiOBr/G and the separation of photogenerated charge carriers. The conditions influencing the photocatalytic performance of Bi/BiOBr/G were also investigated in detail, as well as the photocatalytic mechanism of the degradation.
关键词： Nanocomposites,Semiconductors,Carbon materials,Photocatalytic activity,Visible light
更新于2025-09-23 15:23:52
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2D Ti2C (MXene) as a novel highly efficient and selective agent for photothermal therapy
摘要： Photothermal therapy (PTT) has shown significant potential for anti-cancer modality. In this report, according to our best knowledge, we explore for the first time Ti2C-based MXene as a novel, highly efficient and selective agent for photothermal therapy (PTT). Ti2C superficially modified with PEG was obtained from the layered, commercially available Ti2AlC MAX phase in the process of etching aluminum layers using concentrated HF, and characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HREM) as well as X-Ray photoelectron spectroscopy for chemical analysis (ESCA-XPS). The PEG-coated Ti2C flakes showed a satisfactory photothermal conversion efficacy (PTCE) and good biocompatibility in wide range of the tested concentrations. Through in vitro studies, the PEG-modified Ti2C demonstrated notable NIR-induced ability to cancerous cells’ ablation with minimal impact on non-malignant cells up to the concentration of 37.5 μg ml-1. The applied doses of Ti2C_PEG in our work were even 24 times lower comparing other MXene-based photothermal agents. This work is expected to expand the utility of 2D MXenes to biomedical applications through the development of an entirely novel agents for photothermal therapy.
关键词： photothermal therapy,biological activity,light-to-heat conversion,2D Ti2C MXenes,anticancer therapy
更新于2025-09-23 15:23:52
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Influence of Mg doping on the structural, morphological, optical, thermal, and visible-light responsive antibacterial properties of ZnO nanoparticles synthesized via co-precipitation
摘要： Mg-doped zinc oxide (Zn1-xMgxO, where x = 0.000, 0.001, 0.003, 0.005, and 0.010 M) nanoparticles (MgZnO NPs) were synthesized via a co-precipitation method and subjected to various analyses for application as functional additives in food packaging. The MgZnO NPs were successfully formed at approximately 360 °C and showed an increase in the optical band gap with respect to the increase in the concentration of Mg doping. The X-ray diffraction and scanning electron microscopy analyses of MgZnO NPs confirmed the formation of hexagonal wurtzite structure and rod-like morphology. X-ray photoelectron spectra revealed that the Mg (1s) peaks centered at 1303.35 and 1303.38 eV were ascribed to the presence of Mg2+ replacing Zn2+. Transmission electron microscopy images showed rod shapes with the length of 208–650 nm and width of 84–142 nm. Various concentrations of synthesized MgZnO NPs were investigated against a gram-negative (Escherichia coli - DH5α) bacterial strain under light and dark conditions. Among the studied samples, 0.010 M MgZnO NPs of concentration 3 mg/mL showed the best antibacterial activity under the light condition. MgZnO NPs revealed uneven ridges on the outer surface, which promote the diffusion ability of Zn2+ and increased production of reactive oxygen species, and consequently lead to bacterial lysis. Furthermore, this study demonstrates excellent feasibility for the application of MgZnO NPs as fillers with good antibacterial activity, especially in antimicrobial food packaging applications.
关键词： Mg doping,reactive oxygen species,antibacterial activity,nanorod,ZnO
更新于2025-09-23 15:23:52
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Uso de análisis semicuantitativo en la recidiva local del carcinoma colorrectal mediante PET/TC con 18F-FDG: ?mito o realidad?
摘要： Objective: Recurrence of colorectal cancer is mostly seen within the first 2 years after surgery. The most frequent site of recurrence is the postsurgical areas and its surroundings. The purpose of this study was to evaluate the usefulness of semiquantitative analysis of 18Fluorine fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in determining recurrence of colorectal carcinoma in the operation site. Material and methods: Files of 35 patients with colorectal carcinoma (25 men, 10 women, mean age: 59.25 ± 2.82 years, range: 27-80 years) who were treated with surgery and underwent FDG PET/CT scanning for restaging of colorectal carcinoma and showing increased FDG uptake in the postsurgical area, were retrospectively analysed. Besides calculating SUVmax of the areas showing FDG uptake, SUVmax of physiological colonic activity was also obtained and SUVmax of lesion/SUVmax of colonic wall (RSUVmax), was calculated. Characteristics of FDG uptake were classified according to histological analysis or clinical and imaging follow-up. Results: In 17 of 35 patients (49%) the standard of reference for the final diagnosis was histologic analysis and in 18 (51%), final diagnosis was based on imaging and clinical follow-up. In 15 of 35 patients (43%) the etiology of increased FDG uptake was recurrence and in 20 (57%), FDG accumulation was observed due to benign etiology. The difference between the mean of the results of SUVmax in patients with recurrent disease and with no evidence of recurrence was statistically significant (P = .030). For SUVmax, a cut-off value for recurrence was calculated as 9.51 with a sensitivity of 80% and a specificity of 70%. In terms of RSUVmax results, a statistically significant difference was also observed between mean values in patients with recurrent disease and in those without (P = .002). ROC analysis demonstrated that the best predictive value of RSUVmax for recurrence was 1.75 with a sensitivity of 67% and specificity of 95%. Conclusions: Semiquantitative analysis of FDG PET/CT may be used in detecting recurrent disease of patients with colorectal carcinoma. Eliminating interfering physiological colonic activity in analysis may have an incremental effect on the success of this technique, by means of increasing the specificity.
关键词： Colorectal carcinoma,Physiological activity,Recurrence,Semiquantitative,FDG PET/CT
更新于2025-09-23 15:23:52
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Studies on structural and optical properties of pure and transition metals (Ni, Fe and co-doped Ni–Fe) doped tin oxide (SnO2) nanoparticles for anti-microbial activity
摘要： In this present work, pure and transition metal ions (Ni, Fe and co-doped Ni–Fe) doped SnO2 nanoparticles (NPs) were synthesized using a simple chemical co-precipitation method. Transition metal ions (Ni, Fe and co-doped Ni–Fe) were doped in order to study the influence of structural and optical properties. The synthesized samples were analyzed by using powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, UV–Visible spectroscopy, FT-IR, and photoluminescence spectroscopic techniques. SnO2 crystallites were found to exhibit tetragonal rutile structure with space group P42/mnm (136) with average particle size in the range of 20–30 nm. Also confirmed that all the doped metal ions were incorporated to SnO2. The UV–Vis-NIR spectroscopy revealed a significant red shift in the absorbing band edge due to increase in the amount of Ni, Fe and co-doped Ni–Fe contents. The SEM image shows the morphology of pure and doped (Fe, Ni and Fe–Ni co-doped) SnO2 NPs with large spherical shapes. In FT-IR spectra, the strong peaks are attributed to the antisymmetric stretching mode of O-Sn-O. The PL spectrum exhibits a strong blue emission peak. The antimicrobial studies were investigated against standard bacterial strains and enhanced anti-bacterial activity in doped and co-doped samples was observed, which can be attributed to the ROS and the particles were in the nanoscale regime.
关键词： Antibacterial activity,Photoluminescence,Co-precipitation,Nanoparticle,Co-dopant
更新于2025-09-23 15:23:52
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Functional imaging of visual cortical layers and subplate in awake mice with optimized three-photon microscopy
摘要： Two-photon microscopy is used to image neuronal activity, but has severe limitations for studying deeper cortical layers. Here, we developed a custom three-photon microscope optimized to image a vertical column of the cerebral cortex > 1 mm in depth in awake mice with low (<20 mW) average laser power. Our measurements of physiological responses and tissue-damage thresholds define pulse parameters and safety limits for damage-free three-photon imaging. We image functional visual responses of neurons expressing GCaMP6s across all layers of the primary visual cortex (V1) and in the subplate. These recordings reveal diverse visual selectivity in deep layers: layer 5 neurons are more broadly tuned to visual stimuli, whereas mean orientation selectivity of layer 6 neurons is slightly sharper, compared to neurons in other layers. Subplate neurons, located in the white matter below cortical layer 6 and characterized here for the first time, show low visual responsivity and broad orientation selectivity.
关键词： subplate neurons,deep brain imaging,visual cortex,neuronal activity,three-photon microscopy,GCaMP6s
更新于2025-09-23 15:23:52
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Novel π-conjugated systems based on pyrimidine N-Oxide
摘要： Pyrimidine N-oxide moiety for the first time was used as a heterocyclic core for the construction of π-conjugated molecules with fluorescent properties. For the synthesis of the title compounds a simple two-step protocol starting from readily available 4-fluoro-2-methylpyrimidine N-oxides was elaborated. A series of 17 novel pyrimidine N-oxide derivatives containing various functional substituents and π-conjugated systems of different length were obtained. The title compounds revealed fluorescent properties in visible region, possessing emission maximum up to 575 nm. Deoxygenation of the N-oxide group led to the loss of visible fluorescence. The chemosensor properties towards TFA and a number of metal cations were demonstrated for 3a, the first representative of the title series. Cytotoxic activity against breast adenocarcinoma cell line was found for three pyrimidine N-oxide derivatives 3b,i,n. Pyrimidine N-oxide 3a was shown to possess excellent biocompatibility and capability to enter cells, that makes it a promising structure for development of bioimaging fluorescent probes.
关键词： Anticancer activity,Pyrimidines,π-Conjugated systems,Fluorescence,Knoevenagel condensation,Metal cations
更新于2025-09-23 15:23:52
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Blobs in recurring extreme-ultraviolet jets
摘要： Context. Coronal jets are one type of ubiquitous small-scale activity that is caused by magnetic reconnection in the solar corona. They are often associated with cool surges in the chromosphere. Aims. In this paper, we report our discovery of blobs in the recurrent and homologous jets that occurred at the western edge of the NOAA active region 11259 on 2011 July 22. Methods. The jets were observed in the seven extreme-ultraviolet (EUV) ?lters of the Atmospheric Imaging Assembly instrument aboard the Solar Dynamics Observatory. Using the base-di?erence images of the six ?lters (94, 131, 171, 211, 193, and 335 ?), we carried out the di?erential emission measure (DEM) analyses to explore the thermodynamic evolutions of the jets. The jets were accompanied by cool surges observed in the Hα line center of the ground-based telescope in the Big Bear Solar Observatory. Results. The jets that had lifetimes of 20?30 min recurred at the same place for three times with an interval of 40?45 min. Interestingly, each of the jets intermittently experienced several upward eruptions at the speed of 120?450 km s?1. After reaching the maximum heights, they returned back to the solar surface, showing near-parabolic trajectories. The falling phases were more evident in the low-T ?lters than in the high-T ?lters, indicating that the jets experienced cooling after the onset of eruptions. We identi?ed bright and compact blobs in the jets during their rising phases. The simultaneous presence of blobs in all the EUV ?lters were consistent with the broad ranges of the DEM pro?les of the blobs (5.5 ≤ log T ≤ 7.5), indicating their multi-thermal nature. The median temperatures of the blobs were ～2.3 MK. The blobs that were ～3 Mm in diameter had lifetimes of 24?60 s. Conclusions. To our knowledge, this is the ?rst report of blobs in coronal jets. We propose that these blobs are plasmoids created by the magnetic reconnection as a result of tearing-mode instability and are ejected out along the jets.
关键词： Sun: chromosphere,Sun: corona,Sun: activity
更新于2025-09-23 15:23:52
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Enhanced sunlight photocatalytic performance of ZnO/ZnS binary heterostructure sheets
摘要： The 2D binary heterostructured ZnO/ZnS sheets were prepared via a hydro-thermal synthesis method. The X-ray diffraction results illustrated that ZnS was successfully formed on ZnO sheets. The images captured by field emission scanning electron microscopy showed the granular structure with fine particles on the surface, which increases the contact area between dye solution and catalysts. The EDS spectrum suggested that the surface of the heterojunction was almost entirely coated with ZnS. The UV-vis diffuse reflectance spectra clarified that the ultraviolet and visible absorption of heterostructure were both enhanced. These results all contribute to the efficient methyl orange degradation with the degradation rate of 83 % in 4 h under direct sunlight.
关键词： Binary heterostructure,Sunglight,Photocatalytic activity,Semiconductor
更新于2025-09-23 15:23:52