The narrow visible-light absorption range and a high recombination rate of photo-excited electrons and holes are the main reasons for the confined photocatalytic performance of graphitic carbon nitride (g-C3N4). Here,...
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The narrow visible-light absorption range and a high recombination rate of photo-excited electrons and holes are the main reasons for the confined photocatalytic performance of graphitic carbon nitride (g-C3N4). Here, g-C(3)N(4)samples with nitrogen vacancies were synthesized with a very basic thermal polymerization method, and the resultant nitrogen deficient g-C3N4(g-C3N4-1.0) prepared by adding 1 g NaOH exhibited better activity than original g-C(3)N(4)for tetracycline degradation, because of a lower recombination rate of photo-excited charge carriers and a redshift of the light absorption range. The advances were confirmed by experiments and spin-polarized density functional theory (DFT), which corroborated each other and showed the effect of defect sites on g-C3N4-1.0 by investigating the electronic structure evolution of the system. The sample can be used for tetracycline degradation, and the spin-polarized DFT study helps understand the reaction mechanism.
Vascular stiffening, an early and common characteristic of cardiovascular diseases (CVDs), stimulates vascular smooth muscle cell (VSMC) proliferation which reciprocally accelerates the progression of CVDs. However, t...
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Vascular stiffening, an early and common characteristic of cardiovascular diseases (CVDs), stimulates vascular smooth muscle cell (VSMC) proliferation which reciprocally accelerates the progression of CVDs. However, the mechanisms by which extracellular matrix stiffness accompanying vascular stiffening regulates VSMC proliferation remain largely unknown. In the present study, we examined the role of the intermediate-conductance Ca2+-activated K+ (IKCa) channel in the matrix stiffness regulation of VSMC proliferation by growing A7r5 cells on soft and stiff polydimethylsiloxane substrates with stiffness close to these of arteries under physiological and pathological conditions, respectively. Stiff substrates stimulated cell proliferation and upregulated the expression of the IKCa channel. Stiff substrate-induced cell proliferation was suppressed by pharmacological inhibition using TRAM34, an IKCa channel blocker, or genetic depletion of the IKCa channel. In addition, stiff substrate-induced cell proliferation was also suppressed by reducing extracellular Ca2+ concentration using EGTA or intracellular Ca2+ concentration using BAPTA-AM. Moreover, stiff substrate induced activation of extracellular signal-regulated kinases (ERKs), which was inhibited by treatment with TRAM34 or BAPTA-AM. Stiff substrate-induced cell proliferation was suppressed by treatment with PD98059, an ERK inhibitor. Taken together, these results show that substrates with pathologically relevant stiffness upregulate the IKCa channel expression to enhance intracellular Ca2+ signaling and subsequent activation of the ERK signal pathway to drive cell proliferation. These findings provide a novel mechanism by which vascular stiffening regulates VSMC function.
The ongoing development of nuclear technologies, especially in medical diagnosis, calls for attention to radiation protection. Herein, a MnO2 nanozyme with peroxidase activity was synthesized using hemoglobin (HGB) as...
The ongoing development of nuclear technologies, especially in medical diagnosis, calls for attention to radiation protection. Herein, a MnO2 nanozyme with peroxidase activity was synthesized using hemoglobin (HGB) as the reducing agent and with a facile one-method method. The HGB-MnO2 nanozyme showed good dispersity and near spherical morphology with size of about 5 nm. In addition, the HGB-MnO2 nanozyme showed high colloidal stability and decent scavenging ability on different radicals (DPPH, ABST, hydroxyl, and superoxide radicals). Therefore, the HGB-MnO2 nanozyme can effectively lower the intracellular ROS level, reduce the DNA damage and maintain the cell viability of HUVECs under X-ray irradiation. The in vivo experiments using C57BL/6J mice as the model also revealed a longer survival time in HGB-MnO2 nanozyme treated group under X-ray radiation without causing observable damage to the subjects. Therefore, HGB-MnO2 nanozyme can be considered as an effective and safe formulation for radiation protection.
The Moving Total Least Squares (MTLS) method has been developed to fit for the measurement data contaminated with errors. Different from the moving least squares method which only takes into account the error of depen...
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The Moving Total Least Squares (MTLS) method has been developed to fit for the measurement data contaminated with errors. Different from the moving least squares method which only takes into account the error of dependent variable, MTLS method considers the errors of all the variables, which determines the local approximants in the sense of the orthogonal direction. MTLS method is more reasonable than MLS method for dealing with errors-in-variables (EIV) model. But due to the construction way of local approximants, it is time consuming and difficult to change the order of basis function. This paper presents an Improved Moving Total Least Squares (IMTLS) method, in which Total Least Square (TLS) based on singular value decomposition is introduced to the local approximants. IMTLS achieves the parameter estimation of local approximants using weight matrix instead of weight function with compact support in MTLS method. Several examples of curve and surface fitting are given to demonstrate the performance of IMTLS method. (C) 2015 Elsevier Ltd. All rights reserved.
An enhanced fruit fly optimization algorithm (FOA) with joint search strategies named JS-FOA is proposed to optimize continuous function problems. First, a collaborative group search, which includes a new parameter, i...
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An enhanced fruit fly optimization algorithm (FOA) with joint search strategies named JS-FOA is proposed to optimize continuous function problems. First, a collaborative group search, which includes a new parameter, is conducted to obtain the critical value. Second, a new search strategy similar to biological memory, namely, memory move direction, is proposed to improve solution accuracy. Third, a gradient descent search is used in the collaborative group search to ensure that it does not fall into a local optimum. Finally, a new function, which is similar to the excitation function in a neural network, is proposed to combine the three search strategies. To test the robustness and convergence of the proposed JS-FOA, we used 29 complex continuous benchmark functions. Results show that the proposed JS-FOA outperforms other heuristic algorithms for most functions. The performance of JS-FOA is also evaluated for different parameter values and the results show that parameter values affect convergence speed within a certain range, but do not change the convergence accuracy for the continuous benchmark functions. The proposed JS-FOA may potentially solve high-dimensional optimization problems. (C) 2019 Elsevier B.V. All rights reserved.
Developing triethylamine (TEA) sensors using metal oxide semiconductors (MOS) presents challenges such as achieving high sensitivity, low operating temperatures, and reliable detection of trace TEA. In this study, a n...
Developing triethylamine (TEA) sensors using metal oxide semiconductors (MOS) presents challenges such as achieving high sensitivity, low operating temperatures, and reliable detection of trace TEA. In this study, a novel two-step solvothermal synthesis strategy was developed for the sequential fabrication of δ-MnO 2 nanosheets and δ-MnO 2 /WO 3 (WMn) heterojunction composites. The resulting WMn heterostructure features a unique morphology, where δ-MnO 2 nanosheets are encapsulated within a WO 3 matrix, forming well-defined layered interfaces and abundant active sites. This tailored structure significantly enhances the TEA sensing performance. In particularly, WMn1 sensor achieves an ultrahigh response of 515.37 to 20 ppm TEA at 140 °C. The sensor also exhibits an exceptionally low detection limit of 15.91 ppb, along with rapid response/recovery kinetics and long-term stability. The superior performance is attributed to the formation of n–p heterojunction and the synergistic effects of electronic and chemical sensitization, which optimize charge carrier dynamics, reduce interfacial resistance, and enhance surface reactivity. By focusing on interface engineering in heterojunction-based gas sensors, this study contributes to the strategic design of high-performance sensing materials, with potential applications in environmental monitoring and industrial safety.
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