1,929 research outputs found

    Nanoparticle growth following photochemical α‐ and β‐pinene oxidation at Appledore Island during International Consortium for Research on Transport and Transformation/Chemistry of Halogens at the Isles of Shoals 2004

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    Nanoparticle events were observed 48 times in particle size distributions at Appledore Island during the International Consortium for Atmospheric Research on Transport and Transformation/Chemistry of Halogens on the Isles of Shoals (ICARTT/CHAiOS) field campaign from 2 July to 12 August of 2004. Eighteen of the nanoparticle events showed particle growth and occurred during mornings when peaks in mixing ratios of α‐ and β‐pinene and ozone made production of condensable products from photochemical oxidation probable. Many pollutants and other potential precursors for aerosol formation were also at elevated mixing ratios during these events, including NO, HNO3, NH3, HCl, propane, and several other volatile organic carbon compounds. There were no consistent changes in particle composition, although both submicron and supermicron particles included high maximum concentrations of methane sulfonate, sulfate, iodide, nitrate, and ammonium during these events. Nanoparticle growth continued over several hours with a nearly linear rate of increase of diameter with time. The observed nanoparticle growth rates varied from 3 to 13 nm h−1. Apparent nanoparticle aerosol mass fractions (yields) were estimated to range from less than 0.0005 to almost 1 using α‐ and β‐pinene as the presumed particle source. These apparent high aerosol mass fractions (yields) at low changes in aerosol mass are up to two orders of magnitude greater than predictions from extrapolated laboratory parameterizations and may provide a more accurate assessment of secondary organic aerosol formation for estimating the growth of nanoparticles in global models

    Efficacy of extractives from parts of Ghanaian pawpaw, avocado and neem on the durability of alstonia

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    Conventional preservatives are not only toxic to wood bio-deteriorators, but also to humans and animals. In an effort to find preservatives that are non-toxic to humans and animals, efficacy of water extracts of heartwood of Azadirachta indica (Neem) and leaves of Persea americana (avocado) and Carica papaya (pawpaw) at 0.24%, was tested on the durability of wood of Alstonia boonei by pressure impregnation and buried in a termite-prone field for 5 weeks following a modified EN 252 and Gay et al. (1957). Efficacy was tested on the basis of visual durability ratings, percentage hardness and mass losses of impregnated alstonia wood after burial. Though alstonia wood retained pawpaw extract least, pawpaw extract improved the durability of alstonia wood most. Pawpaw extract could be used to improve the durability of alstonia wood better at 0.72% (3x0.24%) and on triple treatment. 83% of Anloga furniture makers who saw the efficacy of pawpaw extract at 0.72% and on triple treatment, showed a high sense of interest in preservative botanical extracts.Key words: Eco-friendly, termite, efficacy, standardization, percentage hardness loss, percentage mass loss, visual durability rating

    Mechanism(s) Underlying Interactions Between Cattle Manure and Mineral Fertilizer in a Maize Field Soil in Ghana

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    A 70-day laboratory incubation study was conducted to unravel the mechanism(s) underlying synergistic interactions between organic and inorganic nutrient inputs to the soil. Soil from a maize farmer's field at Kpongu in the Upper West Region of Ghana was amended with a factorial combination of 0, 50% and 100% levels of the recommended rates (RR) of inorganic fertilizer and cattle manure and incubated at room temperature in plastic cups. Deionized water was added to maintain soil moisture at 70% field capacity throughout the incubation period. Cups were covered with gas-permeable parafilm. Soil sampling was done at 7, 28, 42, 56 and 70 days after incubation. The soil was analyzed for available phosphorus, organic carbon, microbial biomass carbon, nitrates, ammonium, soil urease activity, iron, and copper at each sampling. The addition of 100% RR NPK + 50% RR manure often results in higher amounts of the measured parameters,synergistic interactions and supply of nutrients to the soil, with longer residual effects. While all the under-studied mechanisms (improved nutrient synchrony, priming effects, general fertility improvement fertility) contribute to synergistic interactions, the improved nutrient synchrony mechanism is the most prominent. Farmers can therefore manage the timing of the nutrient inputs well to capitalize on this mechanism for improved soil fertility.&nbsp

    Detection of Human Genotype “B” Giardia lamblia in Ghanaian Cattle from Frafraha in Adentan Municipality of Ghana

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    Giardia duodenalis is a common intestinal parasite in humans, a wide range of domesticated and wild animals. There are human and animal specific, as well as zoonotic pathogenic gen­otypes. It is not clear whether livestock in close proximity to humans could be infected with human specific genotypes, and vice versa. In this study, Giardia-positive faecal samples were collected from both humans (n = 4) (from Maamobi Polyclinic in the Ayawaso Sub- Metro) and calves (n = 8) (from Animal Research Institute Farms, Adentan Municipality), in Ghana. Nested PCR amplification using Giardia-specific, Glutamate dehydrogenase (GDH) genes and Tri­osephosphate isomerase (TPI) gene primers for human and animal faecal samples respectively was carried out. Results showed that 100% of the calves carried the TPI-B genotype, which is a common pathogenic genotype in humans. This report is based on the unusual results obtained as Giardia duodenalis genotype B is known to occur in humans but is being observed in calves for the first time. This suggests that calves in close proximity to humans could be reservoirs and sources of human Giardia infections

    Usages Et Vulnerabilite De Pterocarpus Santalinoides L'her. Ex De (Papillionoidae), Une Plante Utilisee Dans Le Traitement Des Gastro-Enterites Dans Le Sud Du Benin

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    In West Africa, rural populations depend heavily on woody plant resources to satisfy particular nutritional and therapeutic needs. This study was conducted in South of Benin to identify local knowledge about Pterocarpus santalinoides, and its vulnerability level. Investigations were made using an interview guide followed by observations. 180 professionals were interviewed. It appears from the study that the "African teak" is known as 10 local designations. The species is sought in many areas of use (African medicine, food medicine, carpentry, art, energy and well-being). On medicinal plan, leaves, bark of the trunk and roots are solicited alone or in association with others to treat especially the symptoms related to gastroenteric (diarrhoea, dysentery, vomiting and abdominal cramps). Decoct is the main galenic form adopted for the treatment of these conditions. Considering all the sectors, all its vegetative organs are used. Degree of uses of various organs of this plant is the main causes of its vulnerability. Vulnerability index (Iv) is equal to 2.4. The species is thus identified as vulnerable. It is urgent for its users to adopt a sustainable management approach, in order to preserve African teak

    Steroids, spinal cord and pain sensation.

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    During the whole life, the nervous system is continuously submitted to the actions of different categories of hormones, including steroids. Therefore, the interactions between hormonal compounds and neural tissues are subjected to intense investigations. While a majority of studies focus on the brain, the spinal cord (SC) has received little attention, although this structure is also an important part of the central nervous system, controlling motor and sensory functions. To point out the importance of interactions between hormones and the SC in the regulation of neurobiological activities, we recapitulated and discussed herein various key data, revealing that the pivotal role played by the SC in nociception and pain modulation, directly depends on the SC ability to metabolize and synthesize steroidal molecules. The paper suggests that future investigations aiming to develop effective strategies against chronic pain, must integrate regulatory effects exerted by hormonal steroids on the SC activity, as well as the actions of endogenous neurosteroids locally synthesized in spinal neural networks.journal article2011 Oct 01importe

    Anti-inflammatory and antioxidant properties of the root extract of Carissa edulis (forsk.) Vahl (apocynaceae)

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    Root extracts of Carissa edulis (Forsk.) Vahl (Apocynaceae) are used for the treatment several pathological states including inflammatory disorders. The present study was undertaken to evaluate the effect of an alcoholic extract of C. edulis (CEE) on carrageenan-induced foot oedema in chicks. Also since free radicals and reactive oxygen species are implicated in inflammatory diseases, the anti-oxidant potential of extract was investigated in in vitro experimental models. Oral administration of CEE (30- 300 mg kg-1 p.o.) significantly inhibited carrageenan-induced foot oedemas with a maximal inhibition of 53.8±8.2%. Similarly, the NSAID diclofenac (10-100 mg kg-1, i.p.) and the steroidal anti-inflammatory agent dexamethasone (0.3-3 mg kg-1, i.p ) reduced the total oedema with a maximal inhibition of 62.7±9.1% and 66.4±7.8% respectively. The extract also scavenged DPPH and prevented lipid peroxidation in rat brain homogenates. These results suggest that alcoholic extract of C. edulis exerts in vivo antiinflammatory activity after oral administration and also has antioxidant properties which may contribute to its activity.Journal of Science & Technology (Ghana) Vol. 27 (2) 2007: pp. 6-1
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