Mössbauer, X-ray, electrical and magnetic properties of lithium borosilicate glasses containing iron and manganese Part I. Mössbauer measurements

The effect of the replacement of MnO₂ by Fe₂O₃ on the oxidation states of iron in some lithium borosilicate glasses were studied using Mössbauer spectroscopy. DTA and infrared measurements showed the presence of two glassy phases, one of them containing iron and the other manganese. The Mössbauer spectra were measured at room temperature for all the glass samples. The spectra revealed the presence of Fe ions only in ferric state in both tetrahedral and octahedral coordination. Also, it was observed that the ratio between the number of iron ions in both coordination states has not changed with the increase of MnO₂ content.     

Fast Efficient Method for Radiolabeling of Pindolol with Iodine-125 Using Iodogen Coated Glass Frit

Although ¹²⁵I-hydroxypindolol (¹²⁵I-HYP) has been an excellent probe of adenoceptor function in certain tissues, but ¹²⁵I-pindolol (¹²⁵I-PIN) was found more specific for -adrenoceptor labeling. This study describes a fast and efficient method for radiolabeling of pindolol with iodine-125, where both chloramine-T and iodogen were used as oxidizing agents. The use of iodogen coated glass frit has a great advantage in increasing the radiochemical yield of ¹²⁵I-pindolol and this was attributed to the increase of the interphaces boundary between the solid and liquid. This technique reduces the quantity of iodogen required to produce high radiochemical yield by its half. The radiochemical yield was determined by TLC system using chloroform: acetic acid: water (15:4:1) as developing solvent and by HPLC using reversed phase RP-18 column and acetonitrile: 0.1M ammonium bicarbonate pH 7.5 (1:1) as a mobile phase at flow rate (1ml/min). The radiochemical yield was found to be 48.6 and 62.9% respectively.     

LC-ESI-MS/MS profiling of alkaloids and antiproliferative activity of Pachypoduim lamerei drake leaves

Abstract

In the present study, evaluation of the antiproliferative activity of Pachypodium lamerei Drake leaves (family Apocyaceae) against human breast cancer cell lines MDA-MB-231 was done for the total methanolic extract, crude alkaloidal mixture and ursolic acid using the MTT colorimetric assay. The methanolic extract showed the strongest antiproliferative activity followed by ursolic acid and crude alkaloidal fraction with an IC₅₀ equal to 6.2, 14.55 and 56.3?µg/ml respectively compared to oleocanthal. It is the first record for the LC/ESI-MS/MS alkaloidal profiling of the leaves of P. lamerei. Seven alkaloids were tentatively identified according to their fragmentation patterns. Four alkaloids were related to the parent indole class and two alkaloids belong to the quinoline class in addition to one steroidal alkaloid with a pregnan nucleus. Phytochemical investigation of the methanolic extract led to the isolation of three triterpenoidal compounds including ursolic acid, 11,12-didehydroursolic acid lactone and ursolic acid lactone.     

Facile synthesis of 3-substituted quinazoline-2,4-dione and 2,3-di-substituted quinazolinone derivatives

3-Substituted quinazoline-2,4(1H,3H)-dione and 2,3-di-substituted quinazolineone derivatives attract considerable interest due to their pharmacological properties. In this paper, we report the synthesis of N-substituted-3-nitrophthalimide derivatives II?CIII, the reactions of phthalimide III with amines, hydrazines, and amino acid derivatives to synthesise a small library of 3-substituted-5-nitroquinazoline-2,4(1H,3H)-diones IV?CXIV and 2,3-di-substituted-6-nitro-quinazolineones XVIII?CXIX.     

First principles calculation of the opto-electronic properties of (110) growth axis SiGe superlattices

Using two versions of the first principles full potential linear muffin-tin orbitals method (FPLMTO) which enable an accurate treatment of the interstitial regions, the electronic and optical properties of (110) growth axis Si/SiGe superlattices are investigated. A comparative study with (001) growth axis superlattices is made. In particular, it is found that the bottom of the conduction band (CB) is closer to Γ$\Gamma$ in the (110) system but the optical activity is not enhanced. Furthermore, the absorption spectra of the superlattices are calculated and are found to be quite different from those of bulk Si and Ge but fairly close to their average.     

Easy preparation,characterization and reactions of new 8-chloro-7-formyl-4-oxo-2-phenyl-4H-pyrimido[1,2-a]pyrimidine-3-carbonitrile

8-Chloro-7-formyl-4-oxo-2-phenyl-4H-pyrimido[1,2-a]pyrimidine-3-carbonitrile ( 3 ) is constructed using N-(5-cyano-6-oxo-4-phenyl-1,6-dihydropyrimidin-2-yl) acetamide ( 2 ) via Vilsmeier-Haack formylation reaction. Compound 3 reacted with 3-(triethoxysilyl)propan-1-amine under different conditions. Condensation of pyrimidopyrimidine 3 with thiosemicarbazone derivative gave Schiff base 8 , which upon treating with Vilsmeier-Haack reagent afforded pyrazole carbothioamide 9 . Cyclocondensation of compound 3 with some binucleophiles namely thiocarbohyrazide, hydrazine carbodithioic acid, benzyl hydrazinecarbodithioate and/or 2-thioxopyrimidinone was investigated. Structures of the new synthesized compounds were confirmed by their analytical and spectral data.     

Structural, electronic and optical properties of SrCl2 under hydrostatic stress

The results of first-principles theoretical study of the structural, electronic and optical properties of SrCl₂ in its cubic structure, have been performed using the full-potential linear augmented plane-wave method plus local orbitals (FP-APW+lo) as implemented in the WIEN2k code. In this approach both the local density approximation (LDA) and the generalized gradient approximation (GGA) are used for the exchange-correlation (XC) potential. Also we have used the Engel-Vosko GGA formalism, which optimizes the corresponding potential for band structure calculations. We performed these calculations with and without spin-orbit interactions. Including spin-orbit coupling cause to lifts the triple degeneracy at Γ point and a double degeneracy at X point. Results are given for structural properties. The pressure dependence of elastic constants and band gaps are investigated. The dielectric function, reflectivity spectra and refractive index are calculated up to 30 eV. Also we calculated the pressure and volume dependence of the static optical dielectric constant.