Nanospheres of Ag‐coated Fe3O4 were successfully synthesized and characterized. Photocatalytic properties of Fe3O4@Ag composites have been investigated using steady‐state studies and laser pulse excitations. Accumulation of the electrons in the Ag shell was detected from the shift in the surface plasmon band from 430 to 405 nm, which was discharged when an electron acceptor such as O2, Thionine (TH) or C60 was introduced into the system. Charge equilibration with redox couple such as C60●–/C60 indicated the ability of these core–shell structures to carry out photocatalytic reduction reactions. As well, outer Ag layer could boost charge separation in magnetic core through dual effects of Schottky junction and localized surface plasmonic resonance (LSPR)‐powered band gap breaking effect under sunlight irradiation; resulted in higher photocatalytic degradation of diphenylamine (DPA). The maximum photocatalytic degradation rate was achieved at optimum amount of Ag‐NP loading to products. Adsorption studies confirmed that degradation of DPA dominantly occurred in solution. Moderately renewability of the nanocatalysts under sunlight was due to oxidation and dissolution of the outer Ag layer. 相似文献
Over the past decade, there have been remarkable advances in understanding the signaling pathways involved in cancer development. It is well-established that cancer is caused by the dysregulation of cellular pathways involved in proliferation, cell cycle, apoptosis, cell metabolism, migration, cell polarity, and differentiation. Besides, growing evidence indicates that extracellular matrix signaling, cell surface proteoglycans, and angiogenesis can contribute to cancer development. Given the genetic instability and vast intra-tumoral heterogeneity revealed by the single-cell sequencing of tumoral cells, the current approaches cannot eliminate the mutating cancer cells. Besides, the polyclonal expansion of tumor-infiltrated lymphocytes in response to tumoral neoantigens cannot elicit anti-tumoral immune responses due to the immunosuppressive tumor microenvironment. Nevertheless, the data from the single-cell sequencing of immune cells can provide valuable insights regarding the expression of inhibitory immune checkpoints/related signaling factors in immune cells, which can be used to select immune checkpoint inhibitors and adjust their dosage. Indeed, the integration of the data obtained from the single-cell sequencing of immune cells with immune checkpoint inhibitors can increase the response rate of immune checkpoint inhibitors, decrease the immune-related adverse events, and facilitate tumoral cell elimination. This study aims to review key pathways involved in tumor development and shed light on single-cell sequencing. It also intends to address the shortcomings of immune checkpoint inhibitors, i.e., their varied response rates among cancer patients and increased risk of autoimmunity development, via applying the data from the single-cell sequencing of immune cells. 相似文献
While chaperone activity of alpha-crystallin (α-Crs) is important in maintaining lens transparency that of beta-casein (β-CN) is vital to prevent the development of corpora amylacea (accumulation of amyloid deposits in mammary glands). These two chaperone proteins are amphiphilic, each contains distinct polar and non-polar regions in the structure. While polar domain of α-Crs is highly electropositive, the counterpart domain in β-CN is strongly electronegative. In this study a Bi-chaperone system consisting of α-Crs and β-CN with different molar ratios were used to prevent the chemical-induced insulin aggregation spectroscopically. As shown, α-Crs and β-CN in the Bi-chaperone system exhibit synergistic chaperoning operation which strongly depends to the specific ratio of the chaperone components. The results of both fluorescence study and native gel electrophoresis confirmed the non-covalent interactions between α-Crs and β-CN. Consequently the synergistic activity can be explained with the possible electrostatic interactions between their polar/charged domains which bring them in close proximity, allowing their synergistic chaperoning operation in the Bi-chaperone system. 相似文献
Local circuits in the cortex and hippocampus are endowed with resonant, oscillatory firing properties which underlie oscillations in various frequency ranges (e.g. gamma range) frequently observed in the local field potentials, and in electroencephalography. Synchronized oscillations are thought to play important roles in information binding in the brain. This paper addresses the collective behavior of interacting locally synchronized oscillations in realistic neural networks. A network of five neurons is proposed in order to produce locally synchronized oscillations. The neuron models are Hindmarsh–Rose type with electrical and/or chemical couplings. We construct large-scale models using networks of such units which capture the essential features of the dynamics of cells and their connectivity patterns. The profile of the spike synchronization is then investigated considering different model parameters such as strength and ratio of excitatory/inhibitory connections. We also show that transmission time-delay might enhance the spike synchrony. The influence of spike-timing-dependence-plasticity is also studies on the spike synchronization. 相似文献
In the previous paper, we introduced a new method of gravitational waves (GW) detection (Jalili et al. in Int. J. Theor. Phys.
49(1):84, 2010). In our proposal, we replaced usual Weber’s metallic bar with a cold electronic plasma. We obtained a nonhomogenous differential
equation for tangential electric field, Eφ, that on it GW is known as nonhomogenous term. In this paper we estimate, the dimension of pipe, the electron density and
some other associated parameters for obtaining the best detection. 相似文献
Three new N,S-donor bidentate pyrazolyl-based ligands abbreviated as [PhNCSPz]−, 1, [PhNCSPzMe2]−, 2, and [PhNCSPzPh2]−, 3, have been synthesized in THF by direct mixing of phenylisothiocyanide with suspension of appropriate sodium-pyrazolate salts and characterized by the common spectroscopic and analytical methods. The Cu(II) complexes of these anionic chelate ligands have been characterized and the crystal structure of Cu(PhNCSPz)2, 4, has been determined. The space group of complex is P21c, with a = 5.9313(3), b = 21.206(1) Å, c = 8.0667(4) Å, β = 103.822(1)°. 相似文献
We have studied the effect of impurity on electronic properties of single-walled carbon nanotubes using Density Functional Theory. Electronic band structures and density of states of (4, 4) and (7, 0) carbon nanotubes in the presence of different amount of B and N impurities were calculated. It was found that these impurities have significant effect on the conductivity of carbon nanotubes. The metallic (4, 4) nanotube remains to be metallic after doping with B and N. The electronic properties of small gap semiconducting (7, 0) tube can extensively change in the presence of impurity. Our results indicate that B-doped and N-doped (7, 0) carbon nanotubes can be p-type and n-type semiconductors, respectively. 相似文献
A nanostructured material of the type Au-ZnO-SiO2 is described that consists of ZnO and gold nanoparticles (NPs) dispersed into a silica matrix and used to construct a voltammetric sensor for 4-nitrophenol. The AuNPs and ZnO NPs are anchored onto the silica network which warrants the nanostructures to be stable in various environments. It also facilitates the electron transfer between the electrolyte and the glassy carbon electrode (GCE). The properties of the nanostructure as a modifier for the GCE were investigated by energy dispersive spectrometry, X-ray diffraction spectroscopy, and transmission electron microscopy. It is shown that the nanostructure increases the surface area. Hence, the cathodic and anodic current in differential pulse voltammetry of 4-nitrophenol are considerably enhanced in comparison to a bare GCE. Under optimum conditions, the currents for oxidation and reduction are proportional to the concentration of 4-nitrophenol in the 0.05–3.5 μM and 0.01–1.2 μM concentration ranges, with 13.7 and 2.8 nM detection limits, respectively. The sensor has excellent sensitivity, fast response, long-term stability, and good reproducibility. It is perceived to be a valuable tool for monitoring 4-nitrophenol in real water samples.
Graphical abstract Schematic of voltammetric sensor for 4-nitrophenol. It is based on GCE modified with gold-ZnO-SiO2 nanostructure. It exhibited the improvement in performance for both oxidation and reduction peaks in terms of linearity, concentration range, detection limit, and sensitivity.
Monte Carlo simulations have been carried out for 2-methoxyethanol in an isothermal–isobaric ensemble (NPT) at 298.15 K and
1 atm pressure. The optimized potential for liquid simulation force field parameters has been used for modeling 2-methoxyethanol
and the TIP4P model for water. Intramolecular rotations are described by an analytical potential function fitted to ab initio
energies. It has been shown that the water molecules can form hydrogen bonds between adjacent O atoms of CH3OCH2CH2OH in aqueous media. The self-association of 2-methoxyethanol in aqueous media has been studied by statistical perturbation
theory.
Received: 9 October 2000 / Accepted: 5 January 2001 / Published online: 3 May 2001 相似文献