The application of silica mesoporous structures in drug delivery and the removal of pollutants and organic compounds through catalytic reactions is increasing due to their unique characteristics, including high loading capacities, tunable pores, large surface areas, sustainability, and so on. This review focuses on very well-studied class of different construction mesoporous silica nano(particles), such as MCM-41, SBA-15, and SBA-16. We discuss the essential parameters involved in the synthesis of these materials with providing a diverse set of examples. In addition, the recent advances in silica mesoporous structures for drug delivery and catalytic applications are presented to fill the existing gap in the literature with providing some promising examples on this topic for the scientists in both industry and academia active in the field. Regarding the catalytic applications, mesoporous silica particles have shown some promises to remove the organic pollutants and to synthesize final products with high yields due to the ease with which their surfaces can be modified with various ligands to create appropriate interactions with target molecules. In the drug delivery process, as nanocarriers, they have also shown very good performance thanks to the easy surface functionalization but also adjustability of their porosities to providing in-vivo and in-vitro cargo delivery at the target site with appropriate rate.
Natural phosphate was applied as an efficient and ecofriendly catalyst for the synthesis of tetraketones (2-2.5 h, 90-100 %) and xanthenes (6.5-8.5 h, 84-95 %) via Knoevenagel-Michael cascade reaction of aromatic aldehydes with 1,3-cyclic diketones in water and ethanol, respectively. This protocol provides several advantages over the traditional chemical synthesis, such as simple work-up, easy handling procedure, nontoxicity and stability of catalyst, low cost and environmental friendliness.
Graphical Abstract& Mahmood Tajbakhsh
Cu(NO3)2 supported on natural phosphate, Cu(ii)/NP, was prepared by co-precipitation and characterized. The Cu(ii)/NP catalyzed the synthesis of xanthenes and triazoles. The proposed protocols provided significant economic and environmental advantages.
ABSTRACT:3D The three dimensional building modelling has been an interesting topic of research for decades and it seems that photogrammetry methods provide the only economic means to acquire truly 3D city data. According to the enormous developments of 3D building reconstruction with several applications such as navigation system, location based services and urban planning, the need to consider the semantic features (such as windows and doors) becomes more essential than ever, and therefore, a 3D model of buildings as block is not any more sufficient. To reconstruct the façade elements completely, we employed the high density point cloud data that obtained from the handheld laser scanner. The advantage of the handheld laser scanner with capability of direct acquisition of very dense 3D point clouds is that there is no need to derive three dimensional data from multi images using structure from motion techniques. This paper presents a grammar-based algorithm for façade reconstruction using handheld laser scanner data. The proposed method is a combination of bottom-up (data driven) and top-down (model driven) methods in which, at first the façade basic elements are extracted in a bottom-up way and then they are served as pre-knowledge for further processing to complete models especially in occluded and incomplete areas. The first step of data driven modelling is using the conditional RANSAC (RANdom SAmple Consensus) algorithm to detect façade plane in point cloud data and remove noisy objects like trees, pedestrians, traffic signs and poles. Then, the façade planes are divided into three depth layers to detect protrusion, indentation and wall points using density histogram. Due to an inappropriate reflection of laser beams from glasses, the windows appear like holes in point cloud data and therefore, can be distinguished and extracted easily from point cloud comparing to the other façade elements. Next step, is rasterizing the indentation layer that holds the windows and doors information. After rasterization process, the morphological operators are applied in order to remove small irrelevant objects. Next, the horizontal splitting lines are employed to determine floors and vertical splitting lines are employed to detect walls, windows, and doors. The windows, doors and walls elements which are named as terminals are clustered during classification process. Each terminal contains a special property as width. Among terminals, windows and doors are named the geometry tiles in definition of the vocabularies of grammar rules. Higher order structures that inferred by grouping the tiles resulted in the production rules. The rules with three dimensional modelled façade elements constitute formal grammar that is named façade grammar. This grammar holds all the information that is necessary to reconstruct façades in the style of the given building. Thus, it can be used to improve and complete façade reconstruction in areas with no or limited sensor data. Finally, a 3D reconstructed façade model is generated that the accura...
Natural phosphate (NP) and synthetic fluorapatite phosphate (SFAP) were proposed as stable, inexpensive, readily available and recyclable catalysts for the condensation of 1,2-diamines with 1,2-dicarbonyls in methanol to afford quinoxaline at room temperature. NP provided as high as 92–99% yield for quinoxalines in short reaction times (i.e., 1–45 min), while SFAP created quinoxalines with 87–97% yield in 60–120 min. From the chemical analyses, X-ray fluoresecency, X-ray diffraction, energy dispersive X-ray and Fourier-transform infrared spectroscopy methods, two main phases (CaO, P2O5) appeared in NP together with other low content phases (SiO2, Fe2O3). Compared to other phases, apatite (CaO and P2O5 as Ca10(PO4)6) played a major role in the catalytic activity of NP. SFAP with similar Ca/P atomic ratio showed a relatively lower catalytic activity than NP for the condensation of 1,2-diamine with 1,2-dicarbonyl in methanol at ambient temperature. To investigate the recyclability of catalysts, the surface properties of NP and 6-recycled NP were investigated using scanning electron microscopy, energy dispersive X-ray and Brunauer–Emmett–Teller and Barrett–Joyner–Halenda methods. Some differences were observed in NP and 6-recycled NP’s particle size, surface area, the volume and size of pores, and the content of elements; nevertheless, the use–reuse process did not noticeably change the catalytic property of NP.
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