a borítólapra  Súgó epa Copyright 
European chemical bulletinVol. 3., No.10-12. (2014.)


Classical chemical sciences

  • O. V. Mikhailov :

    The problems concerned with the processes of template synthesis of 3d-element metal aza- and thiazamacrocyclic complexes that happen in nanoreactors on the basis of thin films metal hexacyanoferrate(II)-gelatin-immobilized matrix implants under their contact with water solutions containing various (N,O,S)-donor atomic ligands and organic compounds having one or two carbonyl groups have been considered. It was noted that, in a series of cases, the variety of metal macrocyclic compounds obtained at template synthesis in such specific conditions considerably differs from that of metal macrocycles formed at the conditions traditional for chemical synthesis.

    Keywords: azamacrocyclic metal chelate; thiaazamacrocyclic metal chelate; thin film; molecular structure.

  • Crystal structure of 4-ethyl-1,3-oxazolidine-2-thione1017-1019en [174.55 kB - PDF]EPA-02286-00032-0020

    The crystal structure of 4-ethyl-1,3-oxazolidine-2-thione, C5H9NOS, has been determined from single crystal X-ray diffraction. This compound crystallizes in the monoclinic system, space group P21/c with the unit cell parameters: a = 8.4988(17) A, b = 10.2300(15) A, c = 7.5192(19) A, ß = 96.8299(11) ° and four molecules in the unit cell. In the crystals, a pair of enantiomeric (R)- and (S)-molecules is connected via intermoleculer N1-H···S1 hydrogen bonds of the neighboring thioamide moieties to form a centrosymmetric dimer with an R2 2(8) graph-set motif.

    Keywords: Crystal structure; Hydrogen-bond; Oxazolidine thione; Thioamide; X-ray diffraction

  • Sayed A. Ahmeda ,
    Nadia A. Abdelriheem ,
    Abdou O. Abdelhamid :

    Condensation of sodium (3-oxocycloalkylidene)methenolate with several heterocyclic amines afforded pyrazolo[1,5-a]pyrimidine and pyrazolo[1,5-a]quinazoline derivatives. Also, 2-(2-cycloalkylidenehydrazinyl)-4-substituted-5-(phenyldiazenyl)-thiazole derivatives were synthesized via reaction of hydrazonoyl halides with 2-cycloalkylidene-hydrazinecarbothioamide. Structures of the newly synthesized compounds were elucidated by elemental analysis, spectral data, alternative synthethic routes and chemical transformation whenver possible.

    Keywords: hydrazonoyl halides; aminopyrazoles; pyrazolo[1,5-a]pyrimidines; pyrazolo[1,5-a]quinazolines; imidazo[1,2-a]cycloalka[ e]pyrimidine; hydrazine-carbothioamide; arylazothiazoles

  • Naphthoquinones with benzofuran or benzodioxan ring were obtained from dichloronaphthoquinone and were fully characterized. The new benzodioxanes were tested on 4 cancer cells and one of them, a derivative from methyl pyrogallate was found very cytotoxic for cancer cells.

    Keywords: naphthoquinone; benzofurane; benzodioxine; antitumor activity; cytotoxicity

  • A series of steroidal tetrazole derivatives (7-9) has been obtained by facile and convenient method in a two-step process. All the newly synthesized compounds were characterized by means of elemental analyses, IR, 1H NMR, 13C NMR and MS. The mean surface roughness value (Ra) of compound 9 was found to be 10.32 measured with AFM. Lipinski’s ‘Rule of Five’ analysis and biological score predicted higher intrinsic quality and revealed that these compounds possess good passive oral absorption. The antiproliferative activity was tested in vitro against HeLa (cervical cancer), KCL-22 (myeloid leukemia), MDA-MBA-231 (breast cancer) and normal cell lines, blood peripheral mononuclear (PBMC) by MTT assay. The synthesized compounds exhibited moderate to good activity against the three human cancer cell lines and were found to be nontoxic to the normal cell lines. In addition, the synthesized compounds were tested for their in vitro antioxidant activity by DPPH method in which compound 9 exhibited good antioxidant activity.

    Keywords: Tetrazoles, steroids, anti-tumour activity, antioxidants, DPPH

  • An efficient and mild synthesis of some diverse iminosaccharides of pyrazole has been carried out. Compounds (8a-b) have been synthesized by the treatment of isoniazide with chalcones (6a-b) using [bbim][BF4] ionic liquid as a solvent under microwave irradiation. Compounds (8a-b) on reaction with various aldoses afforded corresponding iminosaccharides compounds containing pyrazole moiety (9al) in presence of ionic liquid under microwaves. The products have been isolated, purified and characterized by different spectral methods i.e. IR, 1H NMR, 13C NMR and Mass spectra. The potent antimicrobial effects (MIC) of the synthesized compounds were investigated.

    Keywords: [bbim][BF4], iminosaccharides, ionic liquid, microwave irradiation, green chemistry

  • Ahmed I. Hashem ,
    Wael S. I. Abou-Elmagd ,
    Ahmed Abd-Elaziz :

    Early, it was found that benzoin condensed with ethyl cyanoacetate in the presence of ethoxide ion to give 3- cyano-3,4-diphenyl-2(5H)- furanone 1. On reinvestigating this reaction, we were able to isolate 1 together with another product, in low yield, which was proved to be 3-cyano-3,4-diphenyl-2(3H)-furanone 2. The latter is formed by isomerization of 1 under the basic conditions employed. Energy calculations revealed that the 2(5H)-furanone 1 is more stable than the 2(3H)-isomer by 24.5 KJ/mole. The behavior of the two furanones 1 and 2 towards some nitrogen nucleophiles viz. hydrazine hydrate, benzylamine and ammonium acetate is studied. The unfavored 1,4 addition of these nucleophiles to the unsaturated carbonyl moiety of 1 is explained in terms of steric and electronic effects of the phenyl group at position 4 .The nitrile groups at position 3 of the furanones 1 and 2 were utilized to construct thiazolidine and tetrazole rings by the action of thioglycollic acid and sodium azide respectively. The structures of all the products obtained were illustrated from their analytical and spectral properties.

    Keywords: 2(5H)-furanone, 2(3H)-furanone, nitrogen, nucleophiles, unfavored 1,4- addition , thiazolidine and tetrazole rings

  • Bakr F. Abdel-Wahab ,
    Hanan A. Mohamed ,
    Ghada E. A. Awad :

    A new series of 3-(4-fluorophenyl)benzo[g]indazoles derivatives have been synthesized by simple, high yielding routes. The key step in the construction of the 3-(4-fluorophenyl)benzo[g]indazoles nucleus involves the reaction of ß-tetralone with 4-fluorobenzaldehyde followed by reaction with hydrazine or thiosemicarbazide. The newly synthesized compounds were evaluated for their antimicrobial activity and compounds 5, 6b, 12d and 16b demonstrated inhibitory effects on the growth of a wide range of microbes.

    Keywords: benzo[g]indazoles, pyrazole, thiazole, antimicrobial activity, minimal inhibitory concentration

  • The oxidation of aliphatic alcohols by tetraamminecopper(II) bis(permanganate) (TACP) in aqueous acetic acid leads to the formation of corresponding carbonyl compounds. The reaction is first order with respect to TACP. A Michaelis-Menten type kinetics is observed with respect to alcohols. The reaction shows a first order dependence on hydrogen ions. The oxidation of [1,1-2H2]ethanol and [2-2H]propan-2- ol exhibits the presence of a substantial primary kinetic isotope effect (kH/kD = 3.52 and 3.96 respectively at 298 K). The rate of disproportionation of the intermediate is susceptible to both polar and steric effects of the substituents. A suitable mechanism has been proposed.

    Keywords: tetraammincopper(II) permanganate; alcohol; oxidation; kinetics; mechanism; correlation analysis

  • Ayaz Mahmood Dar ,
    Vilsmeier-Haack synthesis of new steroidal pyrazoles1104-1106en [176.16 kB - PDF]EPA-02286-00032-0100

    A novel expeditious and convenient synthesis of hitherto unknown 5ß-cholestano [6, 7- c] 5'-methyl-1'-carbothioic acid amido pyrazoles based on the reaction of 5ß-cholestan-6-one thiosemicarbazones with modified Vilsmeier-Haack reagent (H3C-CO-NH2/POCl3) is described. The compounds presented here, are novel scaffolds and have not been described before. Structural assignment of these newly synthesized compounds was performed by IR, 1H NMR, 13C NMR, MS and analytical data. A general mechanistic scheme for these reactions is also suggested based on the current and previous data.

    Keywords: Thiosemicarbazone, pyrazole, Vilsmeier-Haack, acetamide, POCl3

  • An efficient and mild synthesis of some diverse iminosaccharides of pyrazole has been carried out. Compounds (8a-b) have been synthesized by the treatment of isoniazide with chalcones (6a-b) using [bbim][BF4] ionic liquid as a solvent under microwave irradiation. Compounds (8a-b) on reaction with various aldoses afforded corresponding iminosaccharides compounds containing pyrazole moiety (9al) in presence of ionic liquid under microwaves. The products have been isolated, purified and characterized by different spectral methods i.e. IR, 1H NMR, 13C NMR and Mass spectra. The potent antimicrobial effects (MIC) of the synthesized compounds were investigated.

    Keywords: [bbim][BF4], iminosaccharides, ionic liquid, microwave irradiation, green chemistry

  • The alcoholysis of N-acetoxy-N-alkoxycarbamates by methanol or ethanol at 20 – 40 °C yields N,N-dialkoxycarbamates and acetic acid. At the lower temperature the competitive formation of N,N’-bis(alkoxycarbonyl)-N,N’-bis(alkoxy)hydrazines can occur. The alkaline hydrolysis of N,N-dialkoxycarbamates yields NH-N,N-dialkoxyamines.

    Keywords: Nucleophilic substitution at nitrogen, N-acyloxy-N-alkoxycarbamates, alcoholysis, N,N-dialkoxycarbamates, hydrolysis, NH-N,N-dialkoxyamines

  • Atef M. Amer ,
    Sherif I. Askar ,
    Tarek S. Muhdi :

    Reaction of acenaphthenequinone and aceanthrenequinone (1a,b) with diaminomaleonitrile at reflux temperature gave acenatho[1,2- b]pyrazine-8,9-dicarbonitrile and aceanthryleno[1,2-b]pyrazine-10-11-dicarbonitrile (2a,b), respectively. The reaction of 2a,b with hydrazine hydrate afforded the corresponding cyclic products, 8,11-diaminoacenatho[1,2-b]pyrazino[2,3-d]pyridazine and 10,13- diaminoaceanthryleno[1,2b]pyrazino[2,3-d]pyridazine (3a,b). The reaction of 1a,b with p-bromoaniline in presence of ZnCl2 afforded complexes bis(p-bromophenylimino)acenaphthene and -aceanthrene (7a,b). We have also described the synthesis of spiro[2H-aceanthrene- 2,2'-thiazolidine]-1,4'-dione derivatives (8a,b). Reaction of 1b with 1-amino-3-(N,N-dimethylamino)propane, benzylhydrazine and pbromophenylhydrazine has been investigated for studying the utility of products as pharmacological agents. Chemical and spectroscopic evidences for the structures of the new compounds are presented.

    Keywords: Diketones; dinitriles; hydrazones; spiro; thiazolidines

  • Sayaka Yoshiwaka ,
    Shinji Ohisa ,
    Noriyuki Yonezawa ,
    Akiko Okamoto :

    Bridged peri-aroylnaphthalene compounds are satisfactorily synthesized by the reaction of bis(fluorobenzoyl)naphthalene derivatives and catechol without high dilution conditions. The preferential bond formation between the p-positioned carbon atoms of the terminal aromatic rings of peri-aroyl groups by 1,2-dioxybenzene unit shows that the starting molecules take syn-orientation of the aroyl groups along with anti-form. By comparison of the spatial organization of the bridged compound with the corresponding non-bridged homologues, the factors leading to syn-oriented conformation for peri-aroylnaphthalene derivatives in crystal packing are elucidated.

    Keywords: Non-coplanarly aromatic ring accumulation, Bridged structure, Non-dilution synthesis, Syn-conformer, Crystal structure

Materials and environmental chemistry

  • Hybrid magnetic nanomaterial with core-shell structure, where particles of Fe3O4 form the core and polydiphenylamine-2-carboxylic acid is the shell, was obtained for the first time in the interfacial process. According to TEM data Fe3O4/polydiphenylamine-2-carboxylic acid nanoparticles have size 2 d 14 nm. It was found by IR spectroscopy that the polymer shell is formed by C–C - joining into 2- and 4- positions of phenyl rings with respect to nitrogen. The obtained hybrid nanomaterial is superparamagnetic and thermally stable.

    Keywords: interfacial polymerization in situ; core-shell; Fe3O4/polydiphenylamine-2-carboxylic acid hybrid nanoparticles; magnetic nanomaterials; magnetic fluids

  • T. Ravi Sankar ,
    P. T. S. R. K. Prasada Rao :

    Assessment of trace metals in ground water in industrial groundwater in and around Vijayawada, Andhra Pradesh, India was carried out. Samples were collected from 60 bore wells for this study. The present study was made assessing the impacts of industrial activities on the ground water quality in and around Vijayawada A.P. 60 ground water samples are collected from industrial areas of Vijayawada. The following metals, say, Pb, Cu, Ni, Fe, Ag, Zn, Mn, Cd, Cr and Co were analyzed in all the samples, The distribution maps served as important information to understand ecological status of the groundwater systems and for the identification of groundwater quality parameters with concentration above the allowable limits.

    Keywords: Heavy metals, ground water, pollution, Vijayawada, industries

  • P. Shanmuga Praba ,
    J. Jeyasundari ,
    Y. Brightson Arul Jacob :

    Most of the researchers have been reported about the nontoxic biosynthesis of silver nanoparticles using several microorganism and plant extracts. This ecofriendly silver nanoparticles exhibit completely new or improved properties based on specific characteristics such as size, distribution, morphology and many applications. In this research the synthesis of silver nanoparticles using Piper betle has been investigated. We have synthesized silver nano particles using 1 mM silver nitrate solution into the plant extract and characterized by UVvis absorption spectroscopy. The antibacterial efficacy also determined by disc diffusion method with Bacillus cereus, Escherchia coli, Klebsiella pneumonia, Staphylococcus aureus and it showed that high level of inhibition. The most outcome of this research will be suggested that biologically synthesized silver nanoparticle has more effective against various disease causing pathogens

    Keywords: Piper betle, Silver nanoparticles, antibacterial activity

  • S. E. Samra ,
    A. M. El-Nokrashy ,
    A. A. El-Asmy :

    The removal and recovery of Pb2+ and Cd2+ is important for environmental protection and economic reasons. A new method, sorptive flotation, for the removal of Pb2+ and Cd2+ from aqueous solutions and water samples using eggshells as sorbent and oleic acid (HOL) as surfactant has been investigated. The process parameters (solution pH, initial concentration of metal ions, sorbent dose, shaking time, oleic acid (HOL) concentration, and temperature) on the flotation of Pb2+ and Cd2+ were studied in batch system. Under the optimum experimental conditions suggested, the removal of ~ 100 % of Pb2+ and Cd2+ was attained. The procedure was successfully applied for the removal of Pb2+ and Cd2+ from different natural water samples.

    Keywords: Ionic flotation, Eggshells, Cadmium, Lead, Surfactant

  • Melamine formaldehyde resin, MFR, is generally formed in a two stage process by the reaction of melamine and formaldehyde. The first stage reaction is carried out at about 70° - 80°C and pH 9-10; and the second stage involves subsequent polycondensation of the products in an acid medium. In this work, reaction is carried out till the first stage only. Thus, prepared MFR when blended in small proportion into PVA matrix, in-solubilises PVA, forming a well defined PVA-MFR composite. The blend can be cast into films of desired thickness and strength. Nanoparticles of Ag, ZnO and TiO2 were prepared and characterised. Each of the prepared nanoparticles was first blended into aqueous PVA, then blended with MFR, and nanocomposite films obtained. The films were subjected to TGA, FTIR and antimicrobial studies. The PVA-MFR composite films are found to have a high level of antimicrobial activity. Nanocomposites have enhanced antimicrobial activity due to antimicrobial property of nano Ag/ZnO/TiO2 in them. The activity is high, especially against highly resistant gram positive bacteria like Staphylococcus Aureus and Bacillus. The composite has good binding properties, forming stable, chemically resistant, coatings on fabric, paper, glass, polyester etc, rendering them antimicrobial. These films and coatings retain their antimicrobial activity over long period of time. Nano silver immobilised on antimicrobial PVA-MFR, could probably be an effective patch for wound dressings, and surgical mask, which are in great demand. A fine coating of the composite on medical devices can decrease the incidence of medical device related infections.

    Keywords: PVA-MFR composite films; Nanocomposites films, Nanoparticles of Ag, ZnO, TiO2; Characterization; Antimicrobial activity

  • Mosotho J. George :

    Environmental monitoring of metolachlor and atrazine herbicides in water samples has been reported recently with the use of the “bubblein- drop single drop micro-extraction” (BID-SDME) method. This study reports the application of this method coupled with the hot-water extraction for the analysis of the residues of these herbicides from the water and sediment samples obtained in the streams running into the Caledon River in the eastern Free State – South Africa. The method was validated for several figures of merit before application to the real samples: it showed sufficient robustness (RSD 7 % repeatability and reproducibility); sufficient linearity with 0.9991 > R2 > 0.9978, accuracy of 98 % using 5 ng mL-1 atraton CRM in water. The results demonstrated that both these herbicides are widely used in the farms as all the streams had detectable levels of at least one herbicide with concentrations ranging from 5 ng mL-1 to about 30 ng mL-1 for water samples and 1 ng mL-1 to 35 ng mL -1 in the sediment samples with some positive correlation between the abundance in the two media (R2 = 0.8267 for atrazine and 0.9012 for metolachlor). The analyte recoveries from the samples relative to HPLC grade water solutions were higher than 90 % demonstrating sufficient recovery. Some related compounds (simazine, terbutylazine and acetochlor) were also detected in some of these samples, although not quantified for lack of appropriate standards.

    Keywords: bubble-in-drop micro-extraction, hot-water extraction, herbicides monitoring, sediments, farming area, Lesotho

  • S. John Mary ,
    R. Nagalakshmi ,
    Susai Rajendran ,
    R. Epshipha :
    High entropy alloys and corrosion resistance-a bird's eye view1131-1135en [122.51 kB - PDF]EPA-02286-00032-0210

    The introduction of high entropy alloys (HEA) concept broke up the traditional rule that the main elements take up more than 50% atomic content. HEA means that alloys are composed of multi elements and each takes up a relatively high but less than 35% of atomic content. The properties of this innovative alloy are decided by the combined action of multi elements. HEA tends to form simple crystallization phase. By controlling the composition, it is possible to achieve high-hardness and high-abrasion performance at high temperature, Microstructure and properties of several HEAs prepared by various methods such as powder metallurgy laser cladding etc, are discussed. The corrosion resistance of HEAs is also discussed.

    Keywords: High entropy alloys; corrosion resistance; micro structure; properties, applications

  • Sensing ascorbic acid with DNA/Prussian blue carbon paste electrode1136-1141en [993.85 kB - PDF]EPA-02286-00032-0220

    A simple sensor for the detection of ascorbic acid (AA) has been developed. The electrochemical behaviours were studied after successfully constructing the electrode through DNA electro-deposition on carbon paste electrode using Prussian blue (PB). The electrodes were characterized by Raman spectroscopy that confirmed electro-deposition of PB, functioning as a redox mediator. The detection method was based on DNA damage induced by hydroxyl radical generated by Fenton reaction in which ascorbic acid effectively scavenges the hydroxyl radical. The amount of DNA damage is proportional to the amount of ascorbic acid concentration which was analyzed by cyclic voltametry (CV). Obtained results show that DNA-based biosensor can be utilized for estimating ascorbic acid in vitamin-c tablets. The detection range of this biosensor was in the range of 1.14 µM to 12.54 µM. Interference effects and stability of the biosensor were also investigated, results show that the biosensor has high sensitivity and selectivity towards ascorbic acid concentrations.

    Keywords: DNA, Ascorbic Acid (AA), vitamin-c tablets, electrochemical, sensor, carbon paste electrode

Chemical and biological aspects of life

  • Sufia Naseem ,
    Manzoor Ahmad Gatoo ,
    Ayaz Mahmood Dar ,
    Khusro Qasim :
    In vivo toxicity if naniparticles-modalities and treatment992-1000en [237.05 kB - PDF]EPA-02286-00032-0230

    In the present scenario, the burgeoning field of nanotechnology is playing central role in various real world applications. Researches engrossing nanoparticles are evolving at a rapid pace owing to which engineered nanomaterials are increasingly becoming part of daily life in the form of cosmetics, food packaging, drug delivery, therapeutics, biosensors, etc. It is intrigued that the properties of nanoparticles which bestow them their unique physicochemical characteristics could also lead to adverse biological consequences such as increased uptake and interaction with the biological systems. Nanomaterials, due to their small size could enter the body through various semi open anatomical interfaces and can penetrate through cells and organelles and disrupt their normal function, which could lead to tissue inflammation, altered cellular redox balance or even cell death. Nanoparticles unlike larger particles can transverse through the circulatory/lymphatic to various vital organs of the body including nervous systems and brain. Nanomaterials could lead to various allied illnesses including bronchitis, asthma, lung and liver cancer, Parkinson’s disease, Alzheimer’s disease, Crohn’s disease, heart disease and colon cancer. Reckoning with the unprecedented applicability’s of nanomaterials in daily life, avenues for direct or indirect exposures of nanoparticles to human beings increases, which raises concern about their role in vivo toxicity. This necessitates intensive research to have knowledge of the various routes of nanoparticle exposure and their effects upon the human health. This review is an attempt to evaluate the various modes of exposure of nanoparticles in human beings, mechanism of toxicity, their fate inside body and adverse health effects

    Keywords: nanoparticles; surface charge; aggregation; lymphatic, circulatory system and respiratory system

  • Hiroshi Ashihara ,
    Hamako Sasamoto ,
    Shinjiro Ogita :

    Cell density of suspension culture of Larix leptolepis embryogenic cells determined the fate of the development. In a low-density cell culture, somatic embryo development was promoted, but the cells continued to proliferate and formed small spherical cell aggregates in a high-density cell culture. In the present study, we compared the uptake and metabolism of 32P-labelled inorganic phosphate (Pi) by the cells of low- (1 %) and high (10 %)-density cultures during first 30 h. Little difference was found in the uptake of 32 Pi by the cells in both the low- and high density-cultures up to 6 h, but Pi uptake in high-density culture almost ceased at 6 hr after inoculation. In contrast, Pi uptake continued linearly in the low-density culture. 32P was distributed in small molecular organic compounds (mainly nucleotides and sugar phosphates), nucleic acids, phospholipids, and phosphoproteins along with unmetabolized Pi. The incorporation of 32P into nucleotide and phospholipid fractions was significantly higher in the cells of low-density culture at 30 h after inoculation. No marked difference on the endogenous levels of purine and pyrimidine nucleotides was observed in both density cultures. From these results it is speculated that the de novo nucleic acids and phospholipids synthesis required in the conversion of embryonic cells into somatic embryos may be caused by sufficient amounts of Pi from the medium occurring only in cells of the low-density culture. The nucleotide levels in both cultures were similar at least up to 72 h. Therefore, sufficient levels of nucleotides for proliferation may be supplied even in cells of the high-density culture. The involvement of Pi uptake in the phenomena observed in the low- and high-density cultures is discussed.

    Keywords: Larix leptolepis; Pinaceae; Japanese larch; cell culture; somatic embryogenesis; cell density; phosphate; nucleic acid; phospholipid

  • Olawale H. Oladimeji ,
    Francis I. Udom :

    Different herbal preparations of Acalypha wilkesiana var. lace-acalypha (Muell and Arg.) are employed in traditional medicine for the treatment and management of disease conditions such as wounds, tumors, hypertension, inflammations, skin infections, gastroenteritis and many others. Ethyl 3,4,5-trihydroxybenzoate (ethyl gallate) and 1,2,3-benzenetriol (pyrogallol) had previously been isolated from the active fractions of this plant. However, this present study was done to isolate compound(s) from one of the inactive fractions. Hence, a short silica-gel column chromatography of the inactive fraction (5A) furnished a compound designated as 3 [Rf 0.15; [n]20 D 1.0300]. The structure of 3 has been established to be D-arabino-hex-1-enitol-1,5-anhydro-2-deoxy (1,5-anhydro-2-deoxy-D-enopyranose-arabino-hex-1- enitol) by a combination of 1H NMR, 13C NMR, MS and IR spectral techniques. Compound 3 recorded no antibacterial activity against B. subtilis, S. aureus and Ps. aeriginosa. However, it demonstrated very weak antibacterial activities against E. coli and S. typhi. which were slightly better than the activity furnished by 5A. Furthermore, it was observed that 3 was inactive against C. albicans. Surprisingly, the crude extract and butanol fraction generally demonstrated comparably stronger antimicrobial activities than 3 implying that the purification of the crude extract and 5A did not improve the activity demonstrated by 3.

    Keywords: A. wilkesiana var. lace- acalypha; inactive fraction; chromatography; antibacterial; 1,5-anhydro-2-deoxy-D-enopyranosearabino- hex-1-enitol

  • Prashanth Suravajhala ,
    Kshitish Acharya :
    Whither genome sequencing of passer?1086-1087en [33.53 kB - PDF]EPA-02286-00032-0260

    Passer domesticus or the common house sparrow is a passerine with a world-wide distribution. The species do not show an obligatory commensal relationship with human beings. House sparrows have lived successfully around human beings for a long time, often competing well with other birds. In fact, these birds were considered a menace in the past, particularly in the USA. House sparrows may be occasional pollinators of flowers and edible crops, and despite being perceived as anti-farmers, they might actually be assisting in pest control. But in the recent times, the numbers of this bird have been declining in many urban areas because of electromagnetic radiations and other anthropogenic activities. Passer domesticus may suite as one of the models for studies influencing human technological advances on life and commensal life-forms in human habitats. Keeping in view of the good level of interest of obtaining better insights into evolutionary lineages of these birds and in particular understanding the genetics in various contexts (such as MHCs, SNPs, microsatellites, gene expressions and epigenetics), we discuss the challenges in genome sequencing of this bird.

    Keywords: House sparrow; genome sequencing; evolution; comparative genomics; agriculture

Industrial and engineering chemistry, biotechnology

  • Mumuni Amadu ,
    Adango Miadonye :

    As global warming due to anthropogenic greenhouse gases, notably carbon dioxide threatens to take a catastrophic dimension, geological storage of carbon dioxide has been widely accepted as a technically and economically viable remediation strategy. Consequently, targeted geological repositories are saline aquifers, salt caverns, deep unmineable coal seams and depleted oil and gas reservoirs. For storage in depleted oil reservoirs, the stratigraphic trapping capability of overlying low permeability shale is the principal motivating factor for long term containment of anthropogenic gas in oil reservoir until its dissolution and final immobilization by mineral carbonation reactions. Consequently, where the development of the oil reservoir by thermal recovery can lead to thermal pressurization of the cap rock layer, the ability of such a depleted reservoir to contain anthropogenic carbon dioxide must be thoroughly investigated to assess its competency as a proposed geological repository. In this study, seismic theory coupled with that of heat transfer has been used to derive interval velocity for a heavy oil reservoir under thermal recovery. The resulting equation has been validated using published works from literature sources

    Keywords: carbon sequestration, heavy oil reservoir, heat transfer, acoustic logging, carbon dioxide emission

  • Adango Miadonye ,
    Mumuni Amadu :

    In the efforts to mitigate the unprecedented anthropogenic carbon dioxide presence in the atmosphere, the decision to store this greenhouse gas in geologic repositories has received global appreciation with assured technical and financial viability. The implication is that the injection temperature of flue gas in the potential geologic sites will be typically those encountered in combustion power plants. This, obviously has a geomechanical consequence considering the fact that heat transferred from the aquifer to the low permeability cap rock will cause excessive pore pressure build up due to poor pore pressure diffusion characteristics of these rocks. While these low permeability rocks are required to provide stratigraphic trapping mechanisms such excessive pore pressure build up can result in compromising the geomechanical integrity. This article has used heat transfer theories and geomechanical concepts to obtain steady state temperature distribution in cap rocks for temperatures ranging from 50 to 8000C. In so doing, cap rock critical temperatures for tensile and shear failures have been established for a potential on-site gas injection into saline aquifers.

    Keywords: Carbon dioxide, tensile failure, shear failure, steady state, geosequestration, diffusivity, thermophysical