Effect of the sonication and coating time on the photocatalytic degradation of TiO2, TiO2-Ag,and TiO2-ZnO thin film photocatalysts

Abstract

Today, the ultrasound utilizing for material synthesis has been extensively investigated. The unusual acoustic cavitation phenomenon caused by ultrasonic waves has created a new world for the production of high efficiency photocatalysts with new structures. In this study, TiO₂, TiO₂-Ag, and TiO₂-ZnO thin film photocatalysts were prepared using titanium isopropoxide Ti[OCH(CH₃)₂]₄, zinc acetate dehydrates (CH₃COO)₂Zn·2H₂O, and silver nitrate AgNO₃ by a sol–gel method under the ultrasonic irradiation. The prepared photocatalysts were characterized by UV–vis diffuse reflectance spectroscopy, X-ray diffraction, scanning electron microscopy (SEM), and energy dispersive spectroscopy. The SEM images showed that the Ag and ZnO particles were evenly dispersed in the photocatalysts due to the ultrasonic irradiation, and Ag particles were approximately 90?nm, which is relatively small compared to the photocatalysts which is not treated with ultrasonic irradiation. The catalytic activity of the photocatalysts was determined using Acid Red 27 dye. The most excellent catalytic degradation was obtained with TiO₂-ZnO thin film photocatalyst. In comparison to the conventional photocatalyst, the efficiency of photocatalytic activity of the photocatalyst produced under ultrasonication has been increased due to the reduced size of Ag and ZnO and its uniform dispersion.     

Metal-Mediated Base Pairing of Rigid and Flexible Benzaldoxime Metallacycles

Oligonucleotides incorporating a central C-nucleoside with either a rigid or flexible benzaldoxime base moiety have been synthesized, and the hybridization properties of their metallacyclic derivatives have been studied by UV melting experiments. In all cases, the metallated duplexes were less stable than their unmetallated counterparts, and the metallacyclic nucleobases did not show a clear preference for any of the canonical nucleobases as a base-pairing partner. With palladated oligonucleotides, increased flexibility translated to less severe destabilization, whereas the opposite was true for the mercurated oligonucleotides; this reflects the greater difficulties in accommodating a rigid Pd^II-mediated base pair than a rigid Hg^II-mediated base pair within the base stack of a double helix.     

Small shaking table testing and numerical analysis of free-field site response and soil-structure oscillation under seismic loading

Bulletin of Engineering Geology and the Environment - In this study, the accuracy level of geometric scaling factor (herein, λ = 45) selected for the shaking table test model...     

Characterization of Tantalum–Titanium Powders with Universal Powder Bed (UPB) System for Electron Beam Melting Process

Russian Journal of Non-Ferrous Metals - Electron beam melting (EBM) is a powder bed fusion additive manufacturing (AM) technique that produces three-dimensional (3D) parts by fusing metallic...     

Water Regions Extraction from LiDAR Data in Coast

Water regions extraction is of great significance to monitoring,research,planning and development of coastal zones.The conventional method of water regions extraction based on remote sensing image often has poor accuracy in coast because there are large differences among spectral character of different water regions which often change over time as well.To solve this problem,the elevation,intensity and point-density information from the highly accurate 3D mass points of airborne LiDAR was exploited to extract water regions.Firstly,a part of water points were extracted by the characteristics of low density,and then were constrained by the elevation and intensity threshold which came from Statistical table.Secondly,A triangulation network surface model was established based on the water points got from the previous step to describe the elevation trend of water surface.Lastly,all the points which near or behind the surface model was extracted as water points.The result of the accuracy evaluation indicates that the recogniton accuracy of water points is more than 91%.     

Star p-hub median problem with modular arc capacities

We consider the hub location problem, where p hubs are chosen from a given set of nodes, each nonhub node is connected to exactly one hub and each hub is connected to a central hub. Links are installed on the arcs of the resulting network to route the traffic. The aim is to find the hub locations and the connections to minimize the link installation cost. We propose two formulations and a heuristic algorithm to solve this problem. The heuristic is based on Lagrangian relaxation and local search. We present computational results where formulations are compared and the quality of the heuristic solutions are tested.     

Investigations on the Structural Damage in Human Erythrocytes Exposed to Silver,Gold, and Platinum Nanoparticles

Human erythrocytes or red blood cells (RBCs), which constitute 99% of blood cells, perform an important function of oxygen transport and can be exposed to nanoparticles (NPs) entering into the human body during therapeutical applications involving such NPs. Hence, the haemocompatibility of the Ag, Au, and Pt NPs on human RBCs is investigated. The parameters monitored include haemolysis, haemagglutination, erythrocyte sedimentation rate, membrane topography, and lipid peroxidation. The findings suggest that platinum and gold NPs are haemocompatible compared to Ag NPs. Erythrocytes exhibit significant lysis, haemagglutination, membrane damage, detrimental morphological variation, and cytoskeletal distortions following exposure to Ag NPs at a concentration of 100 µg mL^?1. Exposure of Ag⁺ to RBCs shows no lysis or deterioration, implying that the observed toxicity is solely due to NPs. The haemolyzed erythrocyte fraction has the ability to induce DNA damage in nucleated cells. Additionally, multiple pits and depressions are observed on RBC membrane following exposure to Ag NPs (50 µg mL^?1 onwards). Hence, it is apparent that Ag NPs exhibit toxicity on RBCs and on other cells that are exposed to NP‐mediated haemolyzed fractions.     

Design and Expeditious Synthesis of Quinoline-Pyrene-Based Ratiometric Fluorescent Probes for Targeting Lysosomal pH

Intracellular pH plays a significant role in many pathological and physiological processes. A series of quinoline-pyrene probes were synthesized in one-step fashion through an oxonium-ion-triggered alkyne carboamination sequence involving C−C, C−O and C−N bond formation for intracellular pH sensing. The quinoline-pyrenes showed significant red shifts at low pH. Fluorescence lifetime decay measurements of the probes showed decreases in lifetime at pH 4. The probes showed excellent selectivity in the presence of various potential interfering agents such as amino acids and cations/anions. Furthermore, the probes were found to show completely reversible emission behaviour in the window between pH 4 and 7. A morpholine-substituted quinoline-pyrene probe efficiently stained lysosomes with high Pearson correlation coefficients (0.86) with Lysotracker Deep Red DND-99 as a reference. A co-localization study of the probe with Lysotracker DND-99 showed selective intracellular targeting and a shift in fluorescence emission due to acidic lysosomal pH.     

Are antibacterial component additions in etchants and adhesives effective against Streptococcus Mutans?

The aim was to investigate the antibacterial activity of various acids and adhesives with and without antibacterial components against Streptococcus mutans. The antibacterial activities of 35% phosphoric acid (Ultra-Etch), 37% phosphoric acid with benzalkonium chloride (Etch-37), adhesive with chlorhexidine (Peak Universal Bond) and without any agent (PQ1) were investigated by agar-diffusion test. The inhibition-zones were measured after 48 h of incubation. For the tooth-cavity model test; cylindrical cavities were prepared on occlusal dentin surfaces of human molars and divided into four groups (n = 10 cavity/group). Group 1: Ultra-Etch + Peak Universal Bond, Group 2: Ultra-Etch + PQ1, Group 3: Etch-37 + PQ1 were applied. The fourth group without any agent application served as control. The teeth were immersed in 5.8 × 10⁶ cfu/ml of S. mutans solution to infect the cavities for 72 h before the application of the groups. After 72 h, dentin chips were collected from the cavity walls with burs for bacterial counting. Statistical analysis was performed by ANOVA, Bonferroni and Dunnett C tests (p < 0.05). Ultra-Etch and Etch-37 performed similar antibacterial activities in agar-diffusion test. Both acids showed better antibacterial activity compared to adhesives (p < 0.05). The antibacterial activity of PQ1 and Peak Universal Bond was observed to be inactivated by light-polymerization. According to the tooth-cavity model; Group I, II, and III demonstrated reduction in bacterial number and there was no significant difference between them. Antibacterial component additions in etchant and adhesive did not show superior antibacterial activity against S. mutans in both in vitro tests.