Sharif Digital Repository

Quorum Sensing is a cell-to-cell communication pr°Cess depending on cell concentration. Communication among bacterial cells °Ccurs through small molecular signals called autoinducers. The consequences of quorum sensing include the activation of pathogenic properties and activation of the gene for biofilm formation. Biofilms are aggregations of bacteria that adhere to surfaces through extracellular polymeric substances. Bacteria in the biofilm phase are much more resistant to antimicrobial agents than their free-swimming counterparts (i.e. the bacteria in planktonic form). In this study, first a series of coumarin derivatives were synthesized; but due to low solubility of the synthesized... 

Two new copper(II) complexes, [CuL2] and [Cu(phox)2], were synthesized by reaction of 1-((4-bromophenylimino)methyl)naphthalen-2-ol, HL, and 2-(2′-hydroxyphenyl)-2-oxazoline, Hphox, as ligands and copper(II) acetate mono-hydrate with the ratio 2:1 (ligand:metal), respectively. For characterization and structure determination of synthesized complexes, different techniques were performed such as FT-IR, elemental analyses (CHN), and X-ray crystallography. The geometry around Cu atom is almost square planar in both complexes. The catalytic activity of the complexes was evaluated in azide–alkyne cycloaddition reaction in water without need of any additional agent. The reaction conditions for the... 

The present work was aimed to account a green and eco-friendly synthesis of copper oxide nanoparticles using Salvia hispanica extracts for the first time.The synthesized copper oxide nanoparticles were fully characterized using FT-IR, XRD, FESEM, EDX, TEM and UV-Vis spectroscopy techniques. The average particle size of copper oxide nanoparticles is around 35 nm and shape of nanoparticles are spherical. Biological activity of the synthesized nanoparticles were evaluated in terms of antibacterial assessments against Staphylococcus aureus and Escherichia coli. In the following, the potential antibacterial activity against gram positive (S.aureus) and gram negative (E.coli) bacteria’s were... 

In the first section of the present thesis, a number of novel heterocycles were prepared; they include spirodihydropyridine, spiroindoline-2-thion, and pyrrolopyrimidines. The major advantages of the current investigation encompass high yields, short reaction times, mild reaction conditions and feasibility and low-cost materials. In the second section of this thesis, heterogeneous catalysts based on magnetic nanoparticles coated with organosilanes were synthesized. These catalysts were synthesized by hydrolysis of tetraethyl organosilanes and other organosilicons such as 3-aminopropyl triethoxy silane. The synthesized scaffolds were used to stabilize precious metals as Pd and Cu. The... 

Spirocycles have been employed both as core structures and appended to the periphery of molecules in drug discovery. The major advantage that spirocycles offer as core structures is their inherent three-dimensional nature and concomitant ability to project functionality in all three dimensions. Spirocycles have been employed both as core structures and appended to the periphery of molecules in drug discovery. The major advantage that spiro cyclesoffer as core structures is their inherent three-dimensional nature and concomitant ability to project functionality in all three dimensions. However, to take full advantage of spirocycles, the ability to control stereochemistry at multiple positions... 

Osteoarthritis has always been one of the most common diseases in middle age because it causes severe pain and inflammation in the joints of the body. Cartilage tissue does not have the ability to repair itself. For this reason, fabricating and designing the most efficient, least-expensive, and most convenient methods for the treatment of cartilage defects is always an important issue. Today, there are surgical and injectable methods to relieve pain and initiate the body's natural healing response. But due to the many disadvantages and limitations of these methods, tissue engineering science has turned to modifying these methods or providing new methods. One of these methods is the use of...