865 research outputs found

    Studies on Plant Cover of Wadi Umm El-Rakham in The Northwestern Coast of Egypt

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    The present investigation was carried out to study the phytosociological characteristics of the range land in Wadi Umm El-Rakham, in Northwestern coast of Egypt during spring 2004 - fall 2005. Thirty eight plant species belong to 17 families were found in Wadi Umm El-Rakham. Eighteen species were annuals and 20 species were perennials. A total of 18 species were palatable, the rest were not. Among annulus, 11 species were palatable, whereas among perennials seven species only were palatable. Fresh and dry foliage yield, species density, frequency, herbage cover and the importance value as well as their relative values were determined in the different locations in the wadi (i.e. top, ridge and wadi bed).  All these traits recorded their highest value in the wadi bed location during spring season of both years 2004 and 2005. Meanwhile, the lowest values of all these traits were recorded in the wadi top location. Significant interaction was noticed among the studied factors i.e. year, location and season) in wadi bed location during spring season of both years.      ÂÂ

    Topology Analysis Reveals Supramolecular Organisation of 96 Large Complex Ions into one Geometrical Object

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    It is shown that the highly complex crystal structure of [Ag(4-(pyrrolidin-1-yl)pyridine)2]NO3·1/2H2O, 1, with 12 symmetry-independent Ag+ ions and 96 units of complex ions in a unit cell can be understood by the ubiquitous srs topology, reducing thousands of atom positions into a single geometrical object in one go

    Optical Properties of Bismuth Borate Glasses Doped with Zinc and Calcium Oxides

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    Some bismuth-borate oxide glass' samples were prepared by the fast quenching method, where B2O3 was replaced with equal concentrations of ZnO and CaO. X-ray diffraction (XRD) was used to examine the internal structure and Fourier transform infrared (FTIR) to identify building units and bonds throughout the studied structural matrices. XRD showed that all samples have short range order structural nature, while FTIR demonstrated some of Zn2+ acted as glass network formers and all Bi3+ acted as glass. UV-visible measurements and calculations showed a decreasing in the energy band gap from 3.83 eV to 1.73 eV with decreasing B2O3 content. Also with decreasing B2O3 content, both real refractive index and metallization factor decreased from 3.1 to 1.9 and from 0.56 to 0.71, respectively. For the studied glass' samples, density and molar volume showed inverted behaviors, where the density decreased while the molar volume increases with decreasing B2O3

    Some Chemical Aspects of Tetrahydro-1-thiopyran-4-one Derivatives

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    3,5-Diarylmethylene-2,6-diphenyltetrahydrothiopyran-4-thiones, 2, reacted with two or four moles of bromine to form 3-aryimethylene 5-bromoarylmethylene- 2,6-dipheny1tetrahydrothiopyran- -4-thione, 3, and 3-arylmethylene-5-bromoarylmethylene-2,6-dibromo- 2,6-diphenyltetrahydrothiopyran-4-thione, 5, respectively. Compound 2a reacted with amines giving 2,6-diphenyl-5-iminophenylmethyl- 3-phenylmethylenetetrahydrothiopyran-4-thiones, 6. Diphenydiazomethane and 9-diazofluorene converted 2a into 4-diphenylethylene- 2,6-dipheny1-3,5 diphenylmethylenetetrahydrothiopyran, 7, and 2,6-diphenyl-3,5-diphenylmethylene-4-(9-fluorenylidene) tetrahydrothiopyran, 8, respectively. Compounds 2 with copper-bronze afforded 3,3\u27,5,5\u27-tetraarylmethylene-2,2\u27 ,6,6\u27-tetraphenyl-Lr-thio- 4,4\u27 dipyranylidenes

    Behaviour of 4-(4-acetoaminophenyl)-4-oxobut-2-enoic acid towards carbon and nitrogen nucleophiles and use of these products in the synthesis of some interesting heterocycles

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    The present work is devoted to study the interaction of-aroylacrylic acid derivative (1) with some containing active methylene compounds under Michael reaction conditions and afforded the Michael adducts (2a-e). When compound 1 was allowed to react with cyclohexanone in the presence of ammonium acetate as catalyst, it afforded hydroquinoline derivative (3). Interaction of the acid 1 with highly and moderately reactive hydrocarbons e.g. p-xylene and acetanilide in the presence of anhydrous aluminumchloride under Friedel-Crafts reaction conditions afforded (4a-b). On the other hand, when the acid 1 was allowed to react with benzyl amine in dry benzene yielded 2-benzylamino-4-(4-acetaminophenyl)-4-oxobutanoic acid (5). This later compound was used to synthesize some heterocyclic compounds (7-11). Also, aza Michael adduct (6) used asthe key starting material for the synthesis of some interesting heterocyclic compounds e.g. pyridazinone, oxazinoneand furanone derivatives (13-16)

    Utility of 4-(4-acetoaminophenyl)-4-oxo-but-2-enoic acid to prepare Pyranand Pyridine derivatives as building blocks in Heterocyclic Synthesis

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    The present work is devoted to study the interaction of ÎČ -aroylacrylic acid derivative (1) with malononitrile in the presence of piperidine and/or ammonium acetate, then using the formed compounds as a starting material for synthesizing fused and isolated heterocyclic system. Ithas been established that the ÎČ-aroylacrylic acid (1) reactwith malononitrile in (DMF) in the presence of piperidineas catalyst with formation of 4H-pyran derivative (2). Bychanging the catalyst into ammonium acetate, pyridine derivative (3) has been obtained. When compound (2) wasallowed to react with triethylorthoformate afforded ethoxymethyleneamino-4H-pyran (4). Compound (4) was used askey starting material for synthesizing some interesting annulated and heterocyclic systems (5-8). Also, the maleamic acid derivatives (9) and (15) have been synthesized via the interaction of (2) and (3) with maleic anhydride to study the behavior of the formed maleamic acid derivatives asanalogies of ÎČ-aroylacrylic towards different active methylene compounds under Michael addition reaction (10-14); (16-18)

    Influence of Sunflower Whole Seeds or Oil on Ruminal Fermentation, Milk Production, Composition, and Fatty Acid Profile in Lactating Goats

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    This study aimed to investigate the effect of sunflower seeds, either as whole or as oil, on rumen fermentation, milk production, milk composition and fatty acids profile in dairy goats. Fifteen lactating Damascus goats were divided randomly into three groups (n = 5) fed a basal diet of concentrate feed mixture and fresh Trifolium alexandrinum at 50:50 on dry matter basis (Control) in addition to 50 g/head/d sunflower seeds whole (SS) or 20 mL/head/d sunflower seeds oil (SO) in a complete randomized design. Milk was sampled every two weeks during 90 days of experimental period for chemical analysis and rumen was sampled at 30, 60, and 90 days of the experiment for ruminal pH, volatile fatty acids (tVFA), and ammonia-N determination. Addition of SO decreased (p = 0.017) ruminal pH, whereas SO and SS increased tVFA (p<0.001) and acetate (p = 0.034) concentrations. Serum glucose increased (p = 0.013) in SO and SS goats vs Control. The SO and SS treated goats had improved milk yield (p = 0.007) and milk fat content (p = 0.002). Moreover, SO increased milk lactose content (p = 0.048) and feed efficiency (p = 0.046) compared to Control. Both of SS and SO increased (p<0.05) milk unsaturated fatty acids content specially conjugated linolenic acid (CLA) vs Control. Addition of SS and SO increased (p = 0. 021) C18:3N3 fatty acid compared to Control diet. Data suggested that addition of either SS or SO to lactating goats ration had beneficial effects on milk yield and milk composition with enhancing milk content of healthy fatty acids (CLA and omega 3), without detrimental effects on animal performance. (Key Words: Fatty Acid Profile, Lactating Goats, Milk Composition, Sunflower Seeds, Sunflower Oil

    Amenability of heap leaching technology on uranium extraction from Gattar and El Missikat area, Eastern Desert, Egypt: A kinetic approach

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    Studies of uranium heap leaching from different uranium mineralization situated in Eastern Desert of Egypt was investigated via batch experiments, followed by its optimum condition applicationon column percolationtests.The optimum process operating parameters were implemented on large column scale in order to make more condition control and evaluate the time and reagents needed in the large scale. The results show thatleaching efficiency of GIIattained about 78.3% with 34kg/ton acid consumption in a 44 days period, while leaching efficiency of El-Missikat attained about 86.6% with 28kg/ton acid consumption in a 40 days period.Kinetics reaction models of column tests have been investigated to optimize the column leaching behavior. Based on the leaching results of two mineralized samples, the rate of the uranium metal dissolution is controlled by the chemical reaction and the diffusion reaction but diffusion reaction control was more predominate than a chemical reaction control

    A critical appraisal of molecular xenomonitoring as a tool for assessing progress toward elimination of lymphatic filariasis

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    We used molecular xenomonitoring (MX, detection of filarial DNA in mosquitoes) to evaluate the impact of mass drug administration (MDA) in sentinel locations in Egypt with high (11.5%) and low (4.1%) baseline microfilaria prevalence rates. Blood-fed Culex pipiens were pooled by household and tested for Wuchereria bancrofti DNA by PCR. There was no significant relationship between the infection status of household residents and parasite DNA status of mosquitoes from the same houses. After 5 MDA rounds, parasite DNA rates in mosquitoes in high- and low-prevalence areas were reduced by 93.8% and 100% to 0.19% (95% CI: 0.076–0.382%) and 0% (95% CI: 0–0.045%), respectively. These changes were consistent with decreases in microfilaria prevalence rates in these sites; they provide insight regarding the minimal mosquito DNA rates necessary for sustained transmission of filariasis in Egypt. We conclude that MX is a powerful tool for monitoring the impact of MDA on filariasis endemicity and transmission
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