Depth dose evaluation for prostate cancer treatment using boron neutron capture therapy

Considering the advantages of boron neutron capture therapy (BNCT) in treating prostate cancer, the amount of dose delivered to tumour and healthy tissues must be determined. Therefore, in this study, Monte Carlo analyses were performed to evaluate physical doses of adjacent healthy tissues and prostate tumours located at different depths of reference phantom developed by International Commission on Radiological Protection. According to the results, when prostate depth decreases, the amount of physical dose in tumour increases but the physical doses of healthy organs around the tumour remain constant. As expected, lithium filter decreases the damages to normal tissues. The estimations of physical dose, dose uniformity and dose distribution suggested that using BNCT with a filtered neutron beam could be applicable for prostates locate at the depths less than 7 cm from the body surface, which occurs in 5 % of all subjects.     

Application and developing of iron‐doped multi‐walled carbon nanotubes (Fe/MWCNTs) as an efficient and reusable heterogeneous nanocatalyst in the synthesis of heterocyclic compounds

Iron‐doped multi‐walled carbon nanotubes (Fe/MWCNTs) is an efficient, ecofriendly and reusable heterogeneous nanocatalyst for the one‐pot synthesis of heterocyclic compounds including bis‐spiro piperidines, piperidines, dihydro‐2‐oxopyrroles, pyrazoles and diazepines at room temperature with good to excellent yields. The heterogeneous nanocatalyst was fully characterized by scanning electron microscopy (SEM), X‐ray diffraction (XRD), inductively coupled plasma (ICP) and FT‐IR analysis. Also, the structures of all prepared compounds were characterized by ¹H NMR, ¹³C NMR, FT‐IR, mass spectrometry (MS) and elemental analysis. The major advantages of these protocols are mild and green reaction conditions, short reaction times, clean reaction, operational simplicity, easy purification and good to excellent yields with the reusable heterogeneous nanocatalyst. The catalyst was ten recycled without significant loss of activity.     

Supported benzimidazole‐salen Cu(II) complex: An efficient,versatile and highly reusable nanocatalyst for one‐pot synthesis of hybrid molecules

A novel and efficient nanocatalyst consisting of benzimidazole‐salen Cu(II) complex on surface‐modified silica (BS‐Cu(II)@SiO₂) was prepared. The heterogeneous nanocatalyst was characterized by FESEM, TEM, EDX, FT‐IR, XRD, ICP, and TGA. The nanocatalyst was used for the one‐pot synthesis of some target hybrid molecules. An efficient four component C–H bond activation/[3 + 2] cycloaddition and condensation/cyclization/aromatization sequence toward triazole‐benzimidazole derivatives is disclosed. This methodology provides a general and rapid synthetic route to some new triazole‐benzimidazole hybrids under mild reaction conditions. In addition, the heterogeneous nanocatalyst can be easily separated from the reaction mixture and used several times without noticeable leaching or loss of its catalytic activity. We believe this interesting one‐pot reaction as well as benzimidazole‐salen Cu(II) complex pave the way to the design and synthesis of other new hybrid molecules and metal catalysts, respectively.     

Utility of 6‐Amino‐2‐thiouracils as a Core of Biologically Potent Polynitrogen–Sulfur Fused Heterocycles

One pot three‐component reaction was assisted to form some new pyridopyrimidine derivatives to be investigated as antimicrobial and antitumor agents. The newly synthesized compounds showed high significant antimicrobial activity against the applied strains of both Gram‐positive and Gram‐negative bacteria and fungi. The cytotoxic activity of some compounds was evaluated as inhibitor of growth in both human liver carcinoma and breast cell lines. The results showed that some compounds exhibited very high cytotoxicity against human liver cell line and breast cancer cells.     

Kinetic and thermal studies of removal of CrO 4 2− ions by ettringite

Ettringite was prepared in the presence of various dosages of CrO ₄ ^2? ions at three different temperatures. X-ray diffraction (XRD) and differential scanning calorimetery (DSC) results showed shift in the peaks characterized to ettringite as the result of formation of Cr-substituted ettringite. Substitution of SO ₄ ^2? by CrO ₄ ^2? ions in ettringite crystal resulted in delay in the rate of its formation, as well as reduction in the crystal diameters. However, the crystal diameters and rate of formation of both ettringite and Cr-substituted ettringite were increased by increasing temperature of preparation, and this was confirmed by scanning electron microscope (SEM) micrographs. The thermodynamic parameters: the enthalpy, entropy, and Gibbs free energy changes for substitution process were studied. It is concluded that the removal of chromate ions by ettringite is an endothermic spontaneous process. The positive value of ΔS° suggests increasing in randomness during the removal process.     

Solution equilibria of pyridinecarboxylic acids: Complexation reaction of 2-mercaptonicotinic acid-copper (II) complex with thiosalicylic acid

The reaction of 2-mercaptonicotinic-copper (II) complex (Cu²⁺-MENA, 1 3n 1) with thiosalicylic acid (TSA) has been investigated spectrophotometrically in ethanol-water solution (50%, v/v) at I=O.IM (NaClO₄) and 25°C. Under the acidic conditions encountered in this study, there are competing equilibria between protonation of the Cu²⁺-MENA binary chelate, the formation of the Cu(MENA)(TSA) ternary complex and protonation of the second ligand (TSA). The equilibrium constants for the complexation reactions and the stability of the mixed-ligand complex are determined. The optimum conditions for the predominance of the ternary complex are established and the enhancement of this complex over binary complex formation is evaluated. Complex-forming equilibria have also been examined by potentiometric-pH titrations and the experimental data are discussed in relation to various equilibria existing in solution. Structural and bonding features of the mixed-ligand complex are illustrated from considerations of the IR spectral data.