Multielement neutron activation analysis of an iron ore

Multielemental analysis of an iron ore from the Kingdom of Saudi Arabia was carried out using Instrumental Neutron Activation Analysis (INAA) with Ge(Li) detectors. The spectra were analysed with the help of an off-line computer programme. Twenty five elements are observed to be present in the ore. The elements of major interest are Fe, Al and Ca with 51.5%, 3.6% and 2.2% concentrations, respectively.     

ClonedBacillus subtilis alkaline protease (aprA) gene showing high level of keratinolytic activity

TheBacillus subtilis alkaline protease(aprA) gene was previously cloned on a pUBHO-derivative plasmid. High levels of expression and gene stability were demonstrated whenB. subtilis cells were grown on the laboratory medium 2XSG.B. subtilis cells harboring the multicopyaprA gene were grown on basal medium, supplemented with 1 % chicken feather as a source of energy, carbon, and nitrogen. Proteolytic and kera-tinolytic activities were monitored throughout the cultivation time. A high level of keratinolytic activity was obtained, and this indicates that alkaline protease is acting as a keratinase. Furthermore, considerable amounts of soluble proteins and free amino acids were obtained as a result of the enzymatic hydrolysis of feather. Biodegradation of feather waste using these cells represents an alternative way to improve the nutritional value of feather, since feather waste is currently utilized on a limited basis as a dietary protein supplement for animal feedstuffs. Moreover, the release of free amino acids from feather and the secreted keratinase enzyme would promote industries based on feather waste.     

An application of the monostandard epithermal neutron activation technique for the analysis of domestic phosphate ores

The trace elements As, Co, Eu, Ga, La, Sb, Sc, Sm, U and W and the major constituents Fe and Na were determined in four domestic phosphate rocks by the monostandard epithermal neutron activation technique. Samples of 0.1 g were irradiated in the Egyptian 2 MW ERR-1 reactor under Cd cover, and the induced gamma activities measured after 6 h, 7 d and 8 w with a Hp Ge detector coupled to a computerized multichannel analyzer. Uranium has been used as a monostandard due to its relatively high resonance integral value (I₀=274.6 b) and because it is one of the elements to be determined more accurately. The present data are compared with those obtained by instrumental neutron activation analysis (INAA) method performed at Institute of Radiochemistry, Karlsruhe. The observed discrepancies do not exceed 12% in average. The present method is a practical alternative for trace element analysis.     

Qualitative properties of modified equations

Suppose that a consistent one-step numerical method of orderr is applied to a smooth system of ordinary differential equations.Given any integer m 1, the method may be shown to be of orderr + m as an approximation to a certain modified equation. Ifthe method and the system have a particular qualitative propertythen it is important to determine whether the modified equationsinherit this property. In this article, a technique is introducedfor proving that the modified equations inherit qualitativeproperties from the method and the underlying system. The techniqueuses a straightforward contradiction argument applicable toarbitrary one-step methods and does not rely on the detailedstructure of associated power series expansions. Hence the conclusionsapply, but are not restricted, to the case of Runge-Kutte methods.The new approach unifies and extends results of this type thathave been derived by other means: results are presented forintegral preservation, reversibility, inheritance of fixed points.Hamiltonian problems and volume preservation. The techniquealso applies when the system has an integral that the methodpreserves not exactly, but to order greater than r. Finally,a negative result is obtained by considering a gradient systemand gradient numerical method possessing a global property thatis not shared by the associated modified equations.     

On the falsity of a claimed exact analytic formula for the calculation of Voigt spectral line profile

We provide a proof of the falsity of a recently claimed “exact analytic formula” for the calculation of the Voigt line profile [Jian He and Qingguo Zhang, An exact calculation of the Voigt spectral line profile in spectroscopy, J. Opt. A: Pure Appl. Opt. 9 (2007) 565–568]. The subsequent findings and claims based on this erroneous representation of the Voigt line profile should not be considered any further.     

Heterocyclic synthesis via enaminones: Regioselective synthesis of some novel pyrazole,isoxazole, pyrimidine,pyrido[1,2‐a]benzimidazole and pyrazolo[1,5‐a]‐pyrimidine derivatives

2‐Acetylbenzothiazole ( 1 ) reacts with dimethylformamide dimethylacetal (DMF‐DMA) to afford the enaminone 2. Compound 2 reacts regioselectively with some nitrilimines 5a–d and nitrile oxides 6b–d to afford the novel pyrazole and isoxazole derivatives 11a–d and 12b–d, respectively, which react with hydrazine hydrate to give the new pyrazolo[3,4‐d]pyridazine and isoxazolo[3,4‐d]pyridazine derivatives 13a–d and 14b–d, respectively. The enaminone 2 reacts with 1H‐benzimidazole‐2‐acetonitrile ( 17 ) to afford the pyrido[1,2‐a]benzimidazole derivatives 19. Compound 2 reacts also with 5‐amino‐3‐phenylpyrazole ( 20 ) and with guanidine to afford the new pyrazolo[1,5‐a]pyrimidine and the 2‐aminopyrimidine derivatives 22 and 24, respectively. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 417–422, 1999     

Some reactions with ω-bromoacetophenone: Synthesis of Δαβ-butenolide and its transformation into pyrrole derivatives

ω-Bromoacetophenone reacts with the sodium salt of ethyl cyanoacetate to afford α-cyano-β-phenyl-Δ^αβ-butenolide. This butenolide undergoes azo coupling with diazotized aromatic amines (ArNH₂) to afford the hydrazo derivatives. These hydrazo derivatives (ArPh, 4-ClC₆H₄, 4-MeC₆H₄, 4-MeOC₆H₄) were transformed into the corresponding 3(2H)-pyridazinone derivatives on stirring in methanol in the presence of potassium hydroxide. These latter compounds were converted into the corresponding 3-cyano-2,5-dihydroxy-4-phenyl-N-arylpyrrole derivatives on reduction with zinc dust in refluxing acetic acid, presumably via reductive cleavage of the N N bond of the pyridazine followed by recyclization via loss of ammonia.     

The genus Machaerium (Fabaceae): taxonomy,phytochemistry, traditional uses and biological activities

Machaerium, in the family Fabaceae, predominantly is a genus of a Neotropical distribution of trees, shrubs, and lianas occurring from southern Mexico to Brazil and northern Argentina and as far as South America. Several Machaerium species are widely used in traditional medicine and are considered to have multiple medicinal properties. This review aims to provide up-to-date and comprehensive information on the taxonomy, phytochemistry, traditional uses and biological activities of plants in the genus Machaerium.