88 research outputs found

    Frustrated network of indirect exchange paths between tetrahedrally coordinated Co in Ba2 CoO4

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    We present a detailed study of the electronic and magnetic interactions of Ba2CoO4, structurally very uncommon because of the isolated CoO4 distorted tetrahedral coordination. We show the presence of Co(d)-O(p) hybridized states characterized by spin polarized oxygen atoms, with their magnetic moments parallel to that on Co. The calculated isotropic exchange interaction parameters, which include the contributions from ligand spins, demonstrate the presence of a three-dimensional (3D) network of magnetic couplings that are partially frustrated in the identified magnetic ground state. Our results indicate that the dominant indirect exchange mechanism responsible for this ground state is mediated by O atoms along the Co-O »O-Co path

    Effect of Tree Leaves on Rumen Fermentation, Microbial Count and Blood Urea Nitrogen of West African Dwarf Goats

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    This experiment was carried out to assess the effect of Azadirachta indica, Newbouldia laevis and Spondias mombin leaves on rumen fermentation, microbial count and blood urea nitrogen (BUN) of West African Dwarf (WAD) goats. Sixteen WAD bucks (11.6 ? 0.9 kg in body weight) were allocated to 4 treatments: 1) Control and 2) 40 g/day of Azadirachta indica, 3) 40 g/day of Newbouldia laevis and 4) 40 g/day of Spondias mombin leaves arranged in a completely randomised design. The ground leaves were included in concentrate diets served on dry matter basis at 2% of body weight while Panicum maximum was fed ad libitum. The control diet had no tree leaves. Data were collected on chemical composition, rumen fermentation and microbial ecology, and BUN. Saponin was highest (P < 0.05) in S. mombin (8.14%) while A. indica and N. laevis had 5.78% and 1.56%, respectively. Rumen ammonia nitrogen was least (P < 0.05) in goats fed A. indica (8.35 mg/dL) while the highest (P < 0.05) total volatile fatty acid (TVFA) was obtained from goats fed S. mombin with 125.51 mM. Goats fed N. laevis yielded the highest (P < 0.05) acetate with 70.65 mol/100 mol while propionate production was highest (P < 0.05) in the rumen of goats fed S. mombin (27.15 mol/100 mol). Viable bacteria count was lowest (P < 0.05) in rumen of goats fed A. indica (3.95?1012 cfu/ml) while the least (P < 0.05) protozoa population was obtained from the rumen of bucks fed S. mombin (4.18?109 cfu/ml). All goats in the treatments containing tree leaves had higher (P < 0.05) and a rapid increase in BUN between 0 and 6 h post feeding when compared with the Control. It is concluded that feeding ground leaves of S. mombin to goats increases rumen total volatile fatty acid and propionate production and reduces the protozoa population

    Comparative study of the level of bacterial/helminths contamination of vegetables produced from polluted and unpolluted irrigation site of Kano

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    A comparative study was contaminations of five major crops (Lactuca veriso, Darcus carota, Solanum lycopersicum, Phylanthus amarus, Alium cepa) produced from polluted (industrial/residential effluents) Sharada and unpolluted (tube well water)Yarimawa using the method described by FAO, (1979). The result shows that the five crops, produced with polluted water viz, Lactuca veriso, Darcus carota, Solanum lycopersicum Phylanthus amarus, Alium cepa, had mean aerobic plate count of 2.0 x 102 cfu/g, 8.40 x 102 cfu/g , 1.13 x 103 cfu/g , 5.8 x 104 cfu/g cfu/g, 5.7 x 101 cfu/g, respectively, and all the five crops had mean coliform count of 180 MPN/g, while that of unpolluted water had mean aerobic plate count of of 1.22 x 102 cfu/g 5.1 x 102 cfu/g , 1.4 x 102 cfu/g, 1.43 x 102 cfu/g, 1.32 x 101 cfu/g respectively, and had mean coliform count of 30, 21,21, 21 and 21MPN/g respectively. The organisms isolated in all the crops produced with polluted water were E. coli, Salmonella sp, Shigella sp, S. aureus, Ascaris egg, Strongloides and Ancylostoma while E. coli, Shigella sp, S. aureus, wer the organisms isolated in the crops produced with unpolluted water, only Lactuca verosa and Solanum lycopersicum, shows the presence of helmiths in the crops produced with the unpolluted water.Key words: Kano, Bacteria, Helminth, effluent, Yarimawa, Sharad

    Comparative analysis of co-processed starches prepared by three different methods

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    Co-processing is currently of interest in the generation of high-functionality excipients for tablet formulation. In the present study, comparative analysis of the powder and tableting properties of three co-processed starches prepared by three different methods was carried out. The co-processed excipients consisting of maize starch (90%), acacia gum (7.5%) and colloidal silicon dioxide (2.5%) were prepared by co-dispersion (SAS-CD), co-fusion (SAS-CF) and co-granulation (SAS-CG). Powder properties of each co-processed excipient were characterized by measuring particle size, flow indices, particle density, dilution potential and lubricant sensitivity ratio. Heckel and Walker models were used to evaluate the compaction behaviour of the three co-processed starches. Tablets were produced with paracetamol as the model drug by direct compression on an eccentric Tablet Press fitted with 12 mm flat-faced punches and compressed at 216 MPa. The tablets were stored at room temperature for 24 h prior to evaluation. The results revealed that co-granulated co-processed excipient (SAS-CG) gave relatively better properties in terms of flow, compressibility, dilution potential, deformation, disintegration, crushing strength and friability. This study has shown that the method of co-processing influences the powder and tableting properties of the co-processed excipient

    Comparative analysis of co-processed starches prepared by three different methods

    Get PDF
    Co-processing is currently of interest in the generation of high-functionality excipients for tablet formulation. In the present study, comparative analysis of the powder and tableting properties of three co-processed starches prepared by three different methods was carried out. The co-processed excipients consisting of maize starch (90%), acacia gum (7.5%) and colloidal silicon dioxide (2.5%) were prepared by co-dispersion (SAS-CD), co-fusion (SAS-CF) and co-granulation (SAS-CG). Powder properties of each co-processed excipient were characterized by measuring particle size, flow indices, particle density, dilution potential and lubricant sensitivity ratio. Heckel and Walker models were used to evaluate the compaction behaviour of the three co-processed starches. Tablets were produced with paracetamol as the model drug by direct compression on an eccentric Tablet Press fitted with 12 mm flat-faced punches and compressed at 216 MPa. The tablets were stored at room temperature for 24 h prior to evaluation. The results revealed that co-granulated co-processed excipient (SAS-CG) gave relatively better properties in terms of flow, compressibility, dilution potential, deformation, disintegration, crushing strength and friability. This study has shown that the method of co-processing influences the powder and tableting properties of the co-processed excipient

    Synthesis and characterization of Sn‑doped TiO2 flm for antibacterial applications

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    Simple sol–gel method has been exploited to deposit Sn-doped TiO2 thin flms on glass substrates. The resultant coatings were characterized by X-ray difraction (XRD), UV–visible techniques (UV–Vis), Fourier transform infrared spectroscopy (FTIR), and photoluminescence analysis (PL). The XRD pattern reveals an increase in crystallite size of the prepared samples with the increasing doping concentration. A decrease in doping concentrating resulted in the decrease in bandgap values. The diferent chemical bonds on these flms were identifed from their FTIR spectra. The photoluminescence analysis shows an increase in the emission peak intensity with increasing dopant concentration, and this can be attributed to the efect created due to surface states. The prepared samples were tested as antibacterial agent toward both Gram-positive and Gram-negative bacteria like S.aureus (Staphylococcus aureus) and E.coli (Escherichia coli), respectively. The size of the inhibition zones indicates that the sample shows maximum inhibitory property toward E.coli when compared to S.aureus

    Post-harvest management and associated food losses and by-products of cassava in southern Ethiopia

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    Improved (high yield and disease resistant) cassava varieties were introduced into Ethiopia around the onset of the twenty-first century, as a potential food security crop. At present, limited information is available from the country on post-production aspects of the value chain (VC) and related food losses. The lack of such data prevents policymakers and VC actors from taking steps towards improving VC efficiencies, which can have a significant impact on livelihoods and food security. The focus of this study was to examine the prevailing post-harvest practices in the cassava VC in southern Ethiopia and quantify the extent of food losses and associated by-products in the framework of the recently developed ‘food loss and waste protocol’. The majority of the cassava in the study area was processed into dry chips and milled into a composite flour with teff and maize to prepare the staple bread (injera). ‘Critical loss points’ were during sun-drying (4%) and stockpiling at farm and marketplace (30–50%). Insect pest damage was primarily responsible for food losses at farm and market level. The most important insect species infesting dry cassava were identified during the survey. As far as the by-products were concerned, the ratio of leaf:wood (stem and stump):starchy root on a dry matter basis at harvest was 1:6:10. Further emphasis should be on improving processing and storage technologies to reduce food losses and the better recovery and utilisation of by-products, especially the leaves of cassava, which could be a potential source of protein in human diets
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