Mahmoudmalloy2659

A layer of graphene quantum dots (GQDs) was applied on the photoanode of a self-powered photoelectrochemical (PEC) UV photodetector based on TiO2 nanotubes (NTs). The GQDs layer acted as a dual functional layer and improved the photodetector performance by both UV light absorption and blocking the charge carriers recombination at the photoanode/electrolyte interface. The short circuit current density (Jsc) and thereby the responsivity of the PEC UV photodetector was enhanced by 473%. The highest value of the responsivity in this work obtained for the PEC UV photodetector with the dual functional GQDs layer was as much as 42.5 mA W-1. This value is far better than previously reported responsivities of the PEC devices based on TiO2 NTs as a photoanode. This high responsivity was obtained under the illumination of a very low intensity UV light (365 nm, 2 mW cm-2) and 0 V bias. Moreover, the sensitivity of the PEC UV photodetector with the dual functional GQDs layer has been improved by 345%, which is almost 3.5 times higher compared to the sensitivity of its counterpart without the GQDs coating. The devices with the dual functional GQDs layer present a splendid repeatability and stability. The rise time and the decay time of this device were measured to be 0.73 s and 0.88 s under the on/off switching UV LEDs, respectively. The electrochemical impedance spectroscopy (EIS) results prove the role of the GQDs layer as an effective blocking layer on the photoanode, hindering the charge carrier recombination at the photoanode/electrolyte interface. This study shows that application of the dual functional GQDs layer in the PEC UV photodetector based on TiO2 NTs is an effective approach for improving the responsivity and sensitivity of a self-powered PEC UV PD, which brought us the possibility of detecting low UV index radiation and using the self-powered photodetectors in cutting-edge wearable electronic devices for the aim of health, safety and environmental monitoring.A synthetic iron model can process both halogenation and hydroxylation with vague selectivity, which is different from halogenase even though these structures are used for the simulation of halogenase. The key factor of the synthetic oxo-iron model mediated hydroxylation or the halogenation is still under debate. Herein density functional theory calculation is used to investigate the hydroxylation versus halogenation of propylene by the complex [FeIV(O)(TQA)(X)]+ (X = F, Cl, Br). Our results suggest that a concerted rebound mechanism (between the -X and the hydroxyl ligands after the hydrogen abstraction) leads to the formation of two different kinds of products.Oxidation processes of metallic interconnects are crucial to the operation of solid oxide fuel cells (SOFCs), and ferritic Fe-Cr alloy is one of the most important metallic interconnect materials. Based on the ReaxFF reactive potential, the interaction of O2 molecules with three types of surfaces (100, 110, 111) of ferritic Fe-Cr alloy has been studied by classical molecular dynamics at constant O2 concentrations and temperatures. The initial oxidation process is systematically studied according to the analysis of O2 absorption rate, charge variations, charge distributions, mean squared distributions, and oxidation rate. The results reveal that it is easier and faster for the Cr atoms to lose electrons than for the Fe atoms during the oxidation process. The obtained oxidation rate of Cr atoms is larger and the formation of Cr2O3 takes precedence over that of FeO. And the thickness of oxidation layers of different surfaces could be determined quantitatively. We also find that the high O2 concentration accelerates the oxidation process and obviously increases the thickness of oxidation layers, while the temperature has a weaker effect on the oxidation process than the O2 concentration. Moreover, the (110) surface presents the best oxidation resistance compared to the other two surfaces. And the (110) surface is efficient in preventing Fe atoms from being oxidized. Here we explore the initial oxidation process of Fe-Cr alloy and the corresponding results could provide theoretical guides to the related experiments and applications as metallic interconnects.Efficient catalysts play crucial roles in various organic reactions and polymerization. Metal-organic frameworks (MOFs) have the merits of ultrahigh porosity, large surface area, dispersed polymetallic sites and modifiable linkers, which make them promising candidates for catalyzation. This review primarily summarizes the recent research progress on diverse strategies for tailoring MOFs that are endowed with excellent catalytic behavior. These strategies include utilizing MOFs as nanosized reaction channels, metal nodes decorated as catalytic active sites and the modification of ligands or linkers. All these make them highly attractive to various applications, especially in catalyzing organic reactions or polymerizations and they have proven to be effective catalysts for a wide variety of reactions. MOFs are still an evolving field with tremendous prospects; therefore, through the research and development of more modification and regulation strategies, MOFs will realize their wider practical application in the future.Electrospray ionization mass spectrometry is increasingly applied to study the structures and interactions of membrane protein complexes. However, the charging mechanism is complicated by the presence of detergent micelles during ionization. Here, we show that the final charge of membrane proteins can be predicted by their molecular weight when released from the non-charge reducing saccharide detergents. Our data indicate that PEG detergents lower the charge depending on the number of detergent molecules in the surrounding micelle, whereas fos-choline detergents may additionally participate in ion-ion reactions after desolvation. The supercharging reagent sulfolane, on the other hand, has no discernible effect on the charge of detergent-free membrane proteins. Taking our observations into the context of protein-detergent interactions in the gas phase, we propose a charge equilibration model for the generation of native-like membrane protein ions. During ionization of the protein-detergent complex, the ESI charges are distributed between detergent and protein according to proton affinity of the detergent, number of detergent molecules, and surface area of the protein. Charge equilibration influenced by detergents determines the final charge state of membrane proteins. This process likely contributes to maintaining a native-like fold after detergent release and can be harnessed to stabilize particularly labile membrane protein complexes in the gas phase.The incidence of articular cartilage defects is increasing year by year. In order to repair the cartilage tissue at the defect, scaffolds with nanofiber structure and biocompatibility have become a research hotspot. In this study, we designed and fabricated a bi-layer scaffold prepared from an upper layer of drug-dispersed gelatin methacrylate (GELMA) hydrogel and a lower layer of a drug-encapsulated coaxial fiber scaffold prepared from silk fiber (SF) and polylactic acid (PLA). These bi-layer scaffolds have porosity (91.26 ± 3.94%) sufficient to support material exchange and pore size suitable for cell culture and infiltration, as well as mechanical properties (2.65 ± 0.31 MPa) that meet the requirements of cartilage tissue engineering. Cell Cycle inhibitor The coaxial fiber structure exhibited excellent drug release properties, maintaining drug release for 14 days in PBS. In vitro experiments indicated that the scaffolds were not toxic to cells and were amenable to chondrocyte migration. Notably, the growth of cells in a bi-layer scaffold presented two states. In the hydrogel layer, cells grow through interconnected pores and take on a connective tissue-like shape. In the coaxial fiber layer, cells grow on the surface of the coaxial fiber mats and appeared tablet-like. This is similar to the structure of the functional partitions of natural cartilage tissue. Together, the bi-layer scaffold can play a positive role in cartilage regeneration, which could be a potential therapeutic choice to solve the current problems of clinical cartilage repair.Fabricating abundant oxygen vacancies is crucial for non-noble metal oxides to catalyze formaldehyde (HCHO) oxidation at room temperature. Here, a simple one-pot preparation method via solution combustion was found to produce oxygen vacancy-rich Co3O4 catalysts, avoiding delicate defect engineering. The catalyst was evaluated to result in 52% HCHO conversion in a dynamic flow reaction with ∼6 ppm HCHO, which was higher as compared to some other Co3O4 catalysts prepared in three methods of sol-gel, deposition precipitation and thermal decomposition. The optimal catalyst also exhibited high durability with steady HCHO conversion (∼47%) for more than 50 h. The catalyst characterizations revealed that the explosive solution combustion brought out two particular features of Co3O4, namely, the porous network structure with nano-holes and the abundant oxygen vacancies. The latter was demonstrated to increase the reactive oxygen species and to improve the reducibility and the oxygen transport capacity of Co3O4. The two features and the derived properties are beneficial to the activity and durability of Co3O4. The solution combustion method can serve as a simple and feasible way to fabricate abundant oxygen vacancies to provide room-temperature activity of Co3O4 for HCHO elimination at room temperature.The free surface of a thin polymeric film is often unstable and deforms into various micro-/nano-patterns under an externally applied electric field. This paper reviews a recent patterning technique, electrohydrodynamic patterning (EHDP), a straightforward, cost-effective and contactless bottom-up method. The theoretical and numerical studies of EHDP are shown. How the characteristic wavelength and the characteristic time depend on both the external conditions (such as voltage, film thickness, template-substrate spacing) and the initial polymer properties (such as rheological property, electrical property and surface tension) is theoretically and experimentally discussed. Various possible strategies for fabricating high-aspect-ratio or hierarchical patterns are theoretically and experimentally reviewed. Aligning and ordering of the anisotropic polymers by EHDP is emphasized. A perspective, including novelty and limitations of the methods, particularly in comparison to some conventional patterning techniques, and a possible future direction of research, is presented.Due to their great load-bearing capabilities, steel-cement interface structures are commonly employed in construction projects, and power utilities including electric insulators. The service life of the steel-cement interface is always decreasing owing to fracture propagation in the cement helped by steel corrosion. In this paper, a noble crack-resistant solution for steel-cement interfaces utilized in hostile outdoor environments is proposed. A Ce-rich, homogeneous, and thick hydrophobic sealing coating (HSC) is developed on the steel-cement interface after 60 minutes of immersion in a 60 000 ppm CeCl3·7H2O sealing coating solution. The specimens treated with optimized HSC film demonstrate fissure filling, lowest corrosion current (I corr) 2.3 × 10-7 A cm-2, maximum hardness (109 Hv), oxide-jacking resistance (40 years), hydrophobic characteristics, carbonation resistance, and bacterial corrosion resistance, resulting in a crack-free steel-cement interface. This work will pave the way for a new branch of environmentally acceptable coatings for the construction and power industries.