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Methylene blue loaded Cu-tryptone complex nanoparticles: a new glutathione-reduced enhanced photodynamic therapy nanoplatform
摘要： The concentration of intracellular reactive oxygen species directly determines the effect of photodynamic therapy. Reducing intracellular glutathione (GSH) content can increase ROS level. Therefore, it is extremely important to construct a nano-platform that can promote photodynamic therapy by consuming GSH. In this study, we synthesized Cu-tryptone complex nanoparticles (Cu-Try NPs) by a simple green method and demonstrated their ability to consume GSH to increase intracellular ROS for the first time. Photosensitizer methylene blue was loaded onto Cu-Try NPs (Cu-Try/MB NPs) for enhanced photodynamic therapy. Studies in vitro and in vivo illustrated that enhanced photodynamic therapy based on Cu-Try/MB NPs can kill cancer cells effectively.
关键词： glutathione,Cu-tryptone complex nanoparticles,photodynamic therapy
更新于2025-09-19 17:15:36
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Scattering due to uniaxial anisotropic chiral medium-coated PEC cylinder with conducting helix loading
摘要： A perfect electrically conducting (PEC) cylinder (having a circular cross-section) encapsulated with uniaxial anisotropic chiral medium was studied emphasizing the features of scattering. A conducting sheath helix structure having a varying orientation with respect to the optical axis (or pitch angle) was assumed to be at the outermost surface. This allows alterations in scattering patterns. The echo width of the structure was evaluated under the assumption of parallel polarized oblique incidence of waves. The effect on scattering was evaluated under varying chirality and permittivity of the coating medium along with the variations in the helix pitch angle. The obtained results are compared with those achieved by replacing the chiral coating with a simple anisotropic kind of medium (without chirality).
关键词： anisotropic chiral mediums,complex helical structures,Wave scattering
更新于2025-09-19 17:15:36
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Polarized radiative transfer in complex media exposed to external irradiation
摘要： Polarized radiative transfer problems in two-dimensional complex media exposed to external irradiation are numerically investigated. The numerical algorithm used is a discontinuous finite element method (DFEM) where unstructured triangular meshes are applied to discretize the computational domain with irregular geometries. In the DFEM application, the discrete elements are assumed to be separated from each other, the shape functions are locally constructed on each element, and the computation domain is connected by simulating the numerical flux across the inner-element boundaries using the up-winding scheme. Thus the DFEM can eliminate the computation errors in the conventional finite element method (FEM) where the inner-elements are forced to be continuous. In this paper, the derivation of the DFEM discretization for vector radiative transfer equation (VRTE) is presented, the correctness of the DFEM for VRTE is validated, and polarized radiative transfer problems in several irregular media are carried out. The distributions of Stokes vector components and radiative flux are presented and analyzed.
关键词： Complex geometry,Stokes vector component,Participating medium,Polarized radiative transfer,Discontinuous finite element method
更新于2025-09-19 17:15:36
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The improved electrochemiluminescence behavior of glassy carbon electrode via in situ chemical bonding modification
摘要： An in situ chemical bonding method is developed for the electrochemiluminescence (ECL) modification of the oxidized glassy carbon electrode (GCEox). Bare GCE has been activated here via a fierce oxidizing etching to form GCEox. GCEox with numerous cracks and oxygen containing groups exhibits a negatively charged surface, which is tending to attract and react with the specific molecules to form chemical bonds. An ECL molecule Ru-L1 was synthesized and in situ bonded on GCEox surface to fabricate Ru-GCEox. The proposed chemical bonding modification eliminates the interface resistance to improve the electron transfer rate between Ru-L1 and the surface of GCE, which has been demonstrated by the better reversibility of Ru-GCEox than the traditional modified GCEs. The improvement of the ECL behavior of Ru-GCEox is also confirmed by its lower ECL potential than the traditional modified GCEs. Ru-GCEox is reusable to response α-naphthol with an ultrahigh sensitivity for its excellent ECL stability and scraping resistance, which decreases the consumption of Ru-L1. The successful fabrication of Ru-GCEox indicates the method of in situ chemical modification for GCEox can be applied to fabricate various glassy carbon-based sensors via coupling with various specific molecules.
关键词： ruthenium (II) complex,glassy carbon,the interfacial charge transfer,electrochemiluminescence
更新于2025-09-19 17:15:36
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Synthesis of μ <sub/>2</sub> -Oxo-Bridged Iron(III) Tetraphenylporphyrin-Spacer-Nitroxide Dimers and their Structural and Dynamics Characterization by using EPR and MD Simulations
摘要： Iron(III) porphyrins have the propensity to form m2-oxo-dimers, the structures of which resemble two wheels on an axle. Whereas their crystal structure is known, their solution structure and internal dynamics is not. In the present work, the structure and dynamics of such dimers were studied by means of electron paramagnetic resonance (EPR) spectroscopy and quantum chemistry based molecular dynamics (MD) simulations by using the semiempirical tight-binding method (GFN-xTB). To enable EPR investigation of the dimers, a nitroxide was attached to each of the tetraphenylporphyrin cores through a linear and a bent linker. The inter-nitroxide distance distributions within the dimers were determined by continuous-wave (cw)-EPR and pulsed electron–electron double resonance (PELDOR or DEER) experiments and, with the help of MD, interpreted in terms of the rotation of the porphyrin planes with respect to each other around the Fe–O–Fe axis. It was found that such rotation is restricted to the four registers defined by the phenyl substituents. Within the registers, the rotation angle swings between 308 and 608 in the proximal and between 1258 and 1458 in the distal register. With EPR, all four angles were found to be equally populated, whereas the 308 and 1458 angles are strongly favored to the expense of the 608 and 1258 angles in the MD simulation. In either case, the internal dynamics of these dimers thus resemble the motion of a step motor.
关键词： DEER spectroscopy,pulsed dipolar spectroscopy,nitroxide,complex formation,metal centers
更新于2025-09-19 17:15:36
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Hydroxyectoine protects Mn-depleted photosystem II against photoinhibition acting as a source of electrons
摘要： In the present study, we have investigated the effect of hydroxyectoine (Ect-OH), a heterocyclic amino acid, on oxygen evolution in photosystem II (PS II) membrane fragments and on photoinhibition of Mn-depleted PS II (apo-WOC-PS II) preparations. The degree of photoinhibition of apo-WOC-PS II preparations was estimated by the loss of the capability of exogenous electron donor (sodium ascorbate) to restore the amplitude of light-induced changes of chlorophyll fluorescence yield (?F). It was found that Ect-OH (i) stimulates the oxygen-evolving activity of PS II, (ii) accelerates the electron transfer from exogenous electron donors (K4[Fe(CN)6], DPC, TMPD, Fe2+, and Mn2+) to the reaction center of apo-WOC-PS II, (iii) enhances the protective effect of exogenous electron donors against donor-side photoinhibition of apo-WOC-PS II preparations. It is assumed that Ect-OH can serve as an artificial electron donor for apo-WOC-PS II, which does not directly interact with either the donor or acceptor side of the reaction center. We suggest that the protein conformation in the presence of Ect-OH, which affects the extent of hydration, becomes favorable for accepting electrons from exogenous donors. To our knowledge, this is the first study dealing with redox activity of Ect-OH towards photosynthetic pigment–protein complexes.
关键词： Hydroxyectoine,Photoinhibition,Photosystem II,Water-oxidizing complex
更新于2025-09-19 17:15:36
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Complex-surfactant-assisted hydrothermal synthesis of one-dimensional ZnO nanorods for high-performance ethanol gas sensor
摘要： One-dimensional (1D) ZnO nanorods (ZNRs) were synthesized by a facile and effective hydrothermal method using the mixture of sodium dodecyl sulfate (SDS) and polyethylene glycol 400 (PEG400) with a molar ratio of 1:1 as the complex surfactant. The microstructure and morphology were characterized using of X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The results demonstrated that the ZNRs are of a single crystal hexagonal wurtzite structure, having a larger length-to-diameter ratio with more regular surface morphology compared with the ZnO products obtained in the presence of only SDS or PEG400. A possible growth mechanism was proposed based the mediation reaction of the complex surfactant. Gas sensing measurements indicated that the ZNRs assisted by the complex surfactant demonstrated excellent ethanol sensing properties at an optimal operating temperature of 300 °C, which could be ascribed to their large length-to-diameter ratio, one-dimensional structure, and numerous surface defects of oxygen vacancies.
关键词： Zinc oxide,Gas sensor,Ethanol,Nanorods,Complex surfactant
更新于2025-09-19 17:15:36
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A novel optical network model for network burden release and congestion reduction based on passive optical network
摘要： In this article, a new optical network structure coping with network congestion is proposed, which is based on passive optical network, and adopts data storage devices coupled with optical line terminal to release network burden. It is shown by our network performance simulation that this network has many merits such as free-scale, fewer connections, larger clustering coefficient, and smaller average shortest path length in comparison to the passive optical network. The novel network structure can replace the far-end service connections with the near-end ones, reduce congestions in an optical network, and, furthermore, relieve traffic burden in optical backbone and metropolitan area networks.
关键词： duplicate service,uniform content location,complex optical network,congestion reduction,Passive optical network
更新于2025-09-19 17:15:36
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Solubilization of a Hydrophobic Prodrug and the Ultrasound Irradiation Effect to TiO<sub>2</sub> Nanoparticles-Incorporated Polyion Complex Micelles
摘要： Sonodynamic therapy (SDT) using ultrasound irradiation instead of photoactivation as in photodynamic therapy, has emerged as a promising treatment for various types of cancer. We have focused on titanium dioxide nanoparticles (TiO2 NPs) as a sonosensitizer which can generate reactive oxygen species by sonication. TiO2 NPs-incorporated polyion complex micelles were developed for the delivery into the cells. Here, carmofur being a hydrophobic prodrug was solubilized into the micelles. From in vitro experiments, it was confirmed that carmofur-solubilized micelles effectively suppress the cell viability due to the additive effect of the anticancer effect of 5-fluorouracil produced by hydrolysis of carmofur and the SDT effect.
关键词： Sonodynamic Therapy,TiO2 Nanoparticle,Polyion Complex Micelle,Prodrug
更新于2025-09-19 17:15:36
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Formation of a supramolecular charge-transfer complex. Ultrafast excited state dynamics and quantum-chemical calculations
摘要： The formation of a supramolecular complex of bis(18-crown-6)stilbene (1) and 4,4’-bipyridine with two ammoniopropyl N-substituents (3) and the substitution reaction between 1·3 and alkali and alkaline-earth metal perchlorates have been studied using absorption, steady-state fluorescence, and femtosecond transient absorption spectroscopy. The formation of 1·(Mn+)2 complexes in acetonitrile was demonstrated. The weak long-wavelength charge-transfer absorption band of 1·3 completely vanishes upon complexation with metal cations because of disruption of the pseudocyclic structure. The spectroscopic and luminescence parameters, stability and substitution constants were calculated. The relaxation scheme of the 1·3 singlet state excited by a 25 fs laser pulse was proposed. It includes very fast vibrational relaxation and direct (τCT-d = 0.32 ps) and back (τCT-b = 0.51 ps) electron transfer resulting in complete fluorescence quenching. The quantum-chemistry calculations revealed the species taking part in the ET process and elucidated the mechanism of relaxation of the excited complex.
关键词： supramolecular complex,quantum-chemical calculations,femtosecond spectroscopy,charge-transfer,electron transfer
更新于2025-09-19 17:15:36