Mohamed Zaki

Binary and ternary complexes of copper(II) involving promethazine, N,Ndimethyl-3-(phenothiazin-10-yl)propylamine (Prom) and various biologically relevant ligands containing different functional groups, were investigated. The ligands (L) are dicarboxylic acids, amino acids, amides and DNA constituents. The ternary complexes of amino acids, dicarboxylic acids or amides are formed by simultaneous reactions. The results showed the formation of Cu(Prom)(L) complexes with amino acids and dicarboxylic acids. The effect of chelate ring size of the dicarboxylic acid complexes on their stability constants was examined. Amides form both Cu(Prom)(L) complexes and the corresponding deprotonated species Cu(Prom)(LH-1). The ternary complexes of copper(II) with (Prom) and DNA are formed in a stepwise process, whereby binding of copper(II) to (Prom) is followed by ligation of the DNA components. DNA constituents form both 1:1 and 1:2 complexes with Cu (Prom)2+. The stability of these ternary complexes was quantitatively compared with their corresponding binary complexes in terms of the parameters ?log10K. The values of ? log10K indicate that the ternary complexes containing aromatic amino acids were significantly more stable than the complexes containing alkyl-and hydroxyalkyl substituted amino acids. The concentration distribution of various complex species formed in solution was also evaluated as a function of pH. The solid complexes [Cu(Prom)L)] where L = 1,1-cyclobutanedicarboxylic acid (CBDCA), oxalic and malonic acid were isolated and characterized by elemental analysis, infrared, TGA, and magnetic susceptibility measurements. Spectroscopic studies of the complexes revealed that the complexes exhibits square planar coordination with copper(II). The isolated solid complexes have been screened for their antimicrobial activities using the disc diffusion method against some selected bacteria and fungi. The activity data show that the metal complexes are found to have antibacterial and antifungal activity.

Background: Proteins involved in mammalian mitochondrial translation, when compared to analogous bacterial proteins, frequently have additional sequence regions whose structural or functional roles are not always clear. For example, an additional short insert sequence in the bovine mitochondrial initiation factor 2 (IF2mt) seems sufficient to fulfill the added role of eubacterial initiation factor IF1. Prior to our recent cryo-EM study that showed IF2mt to structurally occupy both the IF1 and IF2 binding sites, the spatial separation of these sites, and the short length of the insert sequence, posed ambiguity in whether it could perform the role of IF1 through occupation of the IF1 binding site on the ribosome.

The present study deals with constructing an automatic low-cost crystallizer system. The study
of the produced sample is important to judge the performance of the constructed unit. A well-known TGS
(Tri-Glycine Sulfate) sample was grown and some physical properties of the produced crystal were
measured should be compared with another resemble published results. The growth of TGS crystal is
affected by programmable temperature decrease method, where the solubility decreases as the
temperature be lowered thus the cooling of a supersaturated solution will often produce crystals. Since
rapid cooling may cause the precipitation of amorphous solid or parasite crystals, it is advisable to
surround the crystal growth apparatus with an insulating medium to slow down the rate of cooling (a
foam covering is used in our study.)
Growth program takes nearly 10 to 12 days and is automatically driven by computer which
controls all the growth conditions like stepper motor speed, regulation of temperature decrease (0.5ºC
each 12 hours). The speed of the stepper motor according to the program is 30 RPM (rotation per minute)
in first five days of growth and 15 RPM afterwards.

Garnet nanoparticles Dy2.8Sr0.2Fe5O12 (DySrIG) were prepared by citrate auto-combustion method and characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and differential thermal analysis (DTA). The suitable formation of this garnet in single phase was at 1100oC with crystallite of size 95 nm. The Curie temperature of DySrIG is obtained at 610K. eff was calculated experimentally and?The effective magnetic moment theoretically and they are compatible with each other. The dielectric constant / increases from order 102 at room temperature to 104 at 850K passing by four? transition temperatures. The temperature dependence of the resistivity of DySrIG at different frequencies (f) 100kHz?f?5MHz indicates also the presence /?of 5 transition temperatures which are slightly different from those of data. The resistivity data are frequency independent at f<1MHz. The transition height is decreased by increasing the temperature from ? 5M?cm at 320K and 200kHz to ? 20?cm at 700K. Accordingly, Dy2.8Sr0.2Fe5O12 (DySrIG) is recommended for the use in phase shifter, circulators and microwave applications.

Simple and accurate conductometric titration has been used for determination of the antitussive drug dextromethorphan (Dex), where sodium tetraphenylborate (NaTPB), silicotungstic acid (STA), phosphotungstic acid (PTA), phosphomolybdic acid (PMA) and reineckate ammonium salt (RAS) were used as titrants.

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