186 research outputs found
DABCO as a novel and efficient catalyst for the synthesis of 4(3H)-quinazolinone derivatives
4(3H)-Quinazolinones were synthesized in high to excellent yields through the one-pot condensation of anthranilic acid, trimethyl orthoformate and primary amines in the presence of DABCO under solvent free conditions.KEY WORDS: 4(3H)-Quinazolinone, DABCO (1,4-diazabicyclo[2,2,2]octane), Trimethyl orthoformate, Anthranilic acid Bull. Chem. Soc. Ethiop. 2011, 25(2), 305-308
Heteropolyacids in synthesis of benzoyl hydrazone derivatives
Keggin type of heteropolyacids as green reusable and efficient catalyst was used in the synthesis of benzoyl hydrazones from reaction of benzoic acid hydrazide and aldehyde and ketone derivatives. The synthesis of N-acetyl and N-benzoyl derivatives has also been performed by the reaction of obtained benzoyl hydrazones with acylcholorides in presence of this kind of heteropolyacids
Solvent-free synthesis of xanthene derivatives by Preyssler type heteropolyacid
Dimedone reacted with aromatic aldehydes and 3,4-methylenedioxyphenol or ÎČ-naphthol in the presence of a catalytic amount of Preyssler type heteropolyacid, H14[NaP5W30O110], as a green and reusable catalyst under solvent-free conditions to form a variety of new xanthene derivatives in very good yields.KEY WORDS: Xanthene derivatives, Solvent-free synthesis, Preyssler type heteropolyacid, 3,4-Methylene dioxyphenol, ÎČ-Naphthol, Three-component one-pot reactions Bull. Chem. Soc. Ethiop. 2011, 25(3), 399-406
Improved battery life for context awareness application in smart-phones
The new smart-phones with new operating system and portable sensors support the basis for context awareness systems and applications for handling user activity and user privacy. Nowadays, individuals need new services and real time information anywhere and anytime. Context awareness is an emerging service, which could be able to improve the user experiences in current situation. Context awareness can be considered as location, calendar, user activity and etc. The review of the literature proves that context awareness in mobile phone can be useful and studied as unavoidable service in next generation of smart-phone applications. In this paper, a short review about context awareness in mobile phone is studied, furthermore, we critically analyzed related works of context awareness in smart-phones. The review shows that the most important context in mobile phone is location, which is mostly obtained by using Global Positioning System (GPS) sensor in mobile phones but GPS can significantly increases battery consumption in mobile phones. In this regard, a framework as Improved Battery life in Context Awareness System (IBCS) is proposed to improve battery life and reduce cost of using GPS in context awareness applications based on smart-phones. The review argues the weakness and strength of these studies, and aims to (a) indicate the most important context in mobile phone, (b) reduce the battery consumption of GPS sensor in mobile phone
Copper-catalyzed cyclization reaction: Unique synthesis of condensed thiazoles and selenazoles
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Comparison of continuous and pulse administration of probiotic bacteria potency of Lactobacillus sp., Bacillus thuringiensis and B. cereus in the basal diet on biochemical parameters of Lates calcarifer
This study was conducted with the aim of determining the effect of different probiotics administration on alterations in biochemical parameters of juvenile sea bass (Lates calcarifer). Four hundred and twenty sea bass with an average weight of 34 ± 4.5 g were prepared and randomly divided into seven groups with three replications (40 fish in each replication) and fed with experimental diets for 90 days. The experimental treatments included: group 1 (T1): different Lactobacillus plantarum sp.; group 2 (T2): L. plantarum sp., L. bulgaricus, L. acidophilus and L. rhamnosus in a combined form (combination of lactobacilli); group 3 (T3): the combination of diets 1 and 2 as well as Bacillus cereus and B. thuringiensis which was administered to fish every two weeks; group 4 was the control group without probiotics (C4). In addition, groups 5, 6 and 7 (T5, T6 and T7) were similar to groups 1, 2 and 3 which were continuously fed to fish. The results showed that there was a significant increase in blood serum cholesterol at the end of the experiment in T7 compared to the control group. The calcium level in T3 showed the highest amount compared to other treatments. All treatments showed a decreased amount of total protein at the end of the experiment compared to the control (C4). Moreover, the highest value was related to T6. T7 exhibited the highest amount of triglycerides and glucose at the end of the experiment. In case of liver enzymes, the lowest serum ALP level was found in T1 and the lowest AST in T6, while serum ALT level did not display any significant difference in any group. In cases of Cpk and HDL, the lowest values belonged to T1. In general, it can be concluded that the use of a mixture of probiotics in a pulse administration can cause positive effects on the blood biochemical parameters of L. calcarifer
The Groebke-Blackburn-Bienayme Reaction
Imidazo[1,2a]pyridine is a wellâknown scaffold in many marketed drugs, such as Zolpidem, Minodronic acid, Miroprofen and DSâ1 and it also serves as a broadly applied pharmacophore in drug discovery. The scaffold revoked a wave of interest when Groebke, Blackburn and BienaymĂ© reported independently a new three component reaction resulting in compounds with the imidazo[1,2âa]âheterocycles as a core structure. During the course of two decades the Groebke Blackburn BienaymĂ© (GBBâ3CR) reaction has emerged as a very important multicomponent reaction (MCR), resulting in over a hundred patents and a great number of publications in various fields of interest. Now two compounds derived from GBBâ3CR chemistry received FDA approval. To celebrate the first 20 years of GBBâchemistry , we present an overview of the chemistry of the GBBâ3CR, including an analysis of each of the three starting material classes, solvents and catalysts. Additionally, a list of patents and their applications and a more inâdepth summary of the biological targets that were addressed, including structural biology analysis, is given
Galvanic coupling effects on the corrosion behavior of the 6061 aluminum alloy used in research nuclear reactors
The 6061 alloy is used in different thermomechanical conditions in research nuclear reactors.
Nuclear fuel plates are manufactured by the picture frame technique (PFT) and the 6061 alloy is
used as cladding for the nuclear fuel âsandwichesâ. After the process, these nuclear plates are
placed in a case composed of 6061-T6 alloy. In this work, the galvanic effects of coupling the
6061 alloy in the T6 and PFT conditions on the corrosion behavior was investigated in solutions
of different chloride contents. The results showed that galvanic corrosion was favored due to the
different microstructural features related to these two thermomechanical conditions of the 6061
alloy. The 6061 alloy in the PFT condition was cathodic to the alloy in the T6 condition. Local
electrochemical techniques were useful in characterizing the electrochemical behavior of the
coupled alloys
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