31 research outputs found

    Changes in bulk and surface properties of two biochar types during 12 months of field ageing in two West-African soils

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    The study investigated the changes in properties of rice husk and corn cob biochars applied in urban agricultural field soils in Tamale (northern Ghana) and Ouagadougou (Burkina Faso), respectively. The biochars were both pyrolyzed at 500 °C with a batch reactor. Fine polyethylene mesh (litter bags) filled with 10 g of each type of biochar were buried at 20 cm depth in urban fields trials with a 3 x 2 factorial layout replicated 4 times. Factor 1 involved soil management practices at 3 levels: (1) farmers’ practice (FP), (2) 20 t biochar ha-1 and (3) control (no biochar). The second factor was time (duration) at two levels (6 and 12 months). Aged and fresh biochars were analyzed for volatile matter (VM), ash and fixed carbon (FC) contents, pH, effective cation exchange capacity (ECEC), and total surface acidity (Sa) and basicity (Sb). Dissolved organic carbon contents were determined sequentially by cold (cDOC) and hot water extractions (hDOC), respectively and aromaticities of cold water DOC (cSUVA) and hot water DOC (hSUVA) were determined. There was no significant interaction effect of soil management practices and time on measured ageing biochar properties. Time significantly affected most biochar ageing properties except Sa and Sb in rice husk biochar and ECEC in corn cob biochars at 6 months of exposure. In both biochars, Ash content, Fixed carbon (FC), cDOC, hDOC, cSUVA and hSUVA increased whilst pH and volatile matter contents decreased significantly. The hDOC was 2-3 times higher than cDOC contents for both biochars. Aromaticity of DOC contents of aged rice husk biochar exposed to soil management practices and time in the experimental site in Tamale showed persistence with time compared to corn cob biochar exposed in Ouagadougou experimental site. The results imply that rainfall, soil organic matter contents with interplay of soil minerals are key drivers to ageing and sequestration of these biochars and that these forces act at different scales but driven by time

    Herbal remedy clinical trials in the media: a comparison with the coverage of conventional pharmaceuticals

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    <p>Abstract</p> <p>Background</p> <p>This study systematically compares newspaper coverage of clinical trials for herbal remedies, a popular type of complementary and alternative medicine, with clinical trials for pharmaceuticals using a comparative content analysis. This is a timely inquiry given the recognized importance of the popular press as a source of health information, the complex and significant role of complementary and alternative medicine in individual health-care decisions, and the trend toward evidence-based research for some complementary and alternative medical therapies. We searched PubMed for clinical trials, Lexis/Nexis for newspaper articles in the UK, US, Australia/New Zealand, and Factiva for Canadian newspaper articles from 1995 to 2005. We used a coding frame to analyze and compare 48 pharmaceutical and 57 herbal remedy clinical trials as well as 201 pharmaceutical and 352 herbal remedy newspaper articles.</p> <p>Results</p> <p>Herbal remedy clinical trials had similar Jadad scores to pharmaceutical trials but were significantly smaller and of shorter duration. The trials were mostly studies from Western countries and published in high-ranking journals. The majority of pharmaceutical (64%) and herbal remedy (53%) clinical trials had private sector funding involvement. A minority declared further author conflicts of interest. Newspaper coverage of herbal remedy clinical trials was more negative than for pharmaceutical trials; a result only partly explained by the greater proportion of herbal remedy clinical trials reporting negative results (<it>P </it>= 0.0201; <it>χ</it><sup>2 </sup>= 7.8129; degrees of freedom = 2). Errors of omission were common in newspaper coverage, with little reporting of dose, sample size, location, and duration of the trial, methods, trial funding, and conflicts of interest. There was an under-reporting of risks, especially for herbal remedies.</p> <p>Conclusion</p> <p>Our finding of negative coverage of herbal remedy trials is contrary to the positive trends in most published research based primarily on anecdotal accounts. Our results highlight how media coverage is not providing the public with the information necessary to make informed decisions about medical treatments. Most concerning is the lack of disclosure of trial funding and conflicts of interest that could influence the outcome or reporting of trial results. This lack of reporting may impact the medical research community, which has the most to lose by way of public trust and respect.</p

    Consensus recommendation for mouse models of ocular hypertension to study aqueous humor outflow and its mechanisms

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    Due to their similarities in anatomy, physiology, and pharmacology to humans, mice are a valuable model system to study the generation and mechanisms modulating conventional outflow resistance and thus intraocular pressure. In addition, mouse models are critical for understanding the complex nature of conventional outflow homeostasis and dysfunction that results in ocular hypertension. In this review, we describe a set of minimum acceptable standards for developing, characterizing, and utilizing mouse models of open-angle ocular hypertension. We expect that this set of standard practices will increase scientific rigor when using mouse models and will better enable researchers to replicate and build upon previous findings

    AGRICULTURE AND BIOLOGY JOURNAL OF NORTH AMERICA Microbial degradation potential of some Ghanaian soils contaminated with diesel oil

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    ABSTRACT The experiment was conducted in the laboratory to investigate the degradation of diesel oil in four soils obtained from semi-deciduous forest (Bekwai and Kokofu series) and savanna (Toje and Nyankpala series) zones with the aim to assess the degrading potential of these soils. The soils were contaminated with diesel oil at 10 g oil /kg soil. The contaminated soils were incubated under room temperature and sampled for total aerobic heterotrophic (TAH) bacterial counts, hydrocarbon utilizing bacterial (HUB) populations, and quantity of diesel oil degraded. The TAH bacteria and HUB counts in all the soils increased in response to diesel oil contamination. The TAH bacteria counts in the forest soils took a longer time to reach their peaks than the savanna soils. The cumulative diesel oil degraded gave an upward trend during the period of study. Between 15 and 40 days after incubation the forest soils (Bekwai and Kokofu) degraded more oil than the savanna soils (Toje and Nyankpala). This study revealed that the main factors responsible for differences in degrading abilities of these soils are presence of large populations of hydrocarbon utilizing bacteria, availability of organic carbon, nitrogen and phosphorus. The study also therefore indicated that the Ghanaian soils used in the present investigation have the potential of degrading diesel oil
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