10,684 research outputs found
Synthesis of a Structurally Constrained Endoperoxide having Antimalarial Activity from -Santonin
α-Santonin 3 was successfully converted into a biologically active compound 5b containing an endoperoxide group through a photo-oxygenation approach as a single isomer. It was found that the singlet oxygen afforded the isomer produced by attack from the sterically-hindered face of cyclohexadiene derivative 4. Evidence to this end is presented based on NOE results and the products formed in the photo-oxygenation reaction, as well as the in vitrotesting of 5b for antimalarial activity.Keywords: Santonin, endoperoxide, photo-oxygenation, singlet oxygen
An assessment of diet overlap of two mesocarnivores in the North-West Province, South Africa
We used scat analysis to study the diet of two sympatric medium-sized carnivores: brown hyaena and black-backed jackal, in the NorthWest Province of South Africa. Seven major dietary categories were identified from the scats, with mammal remains being most common for both species. Brown hyaena scats contained more large mammal remains, which together with the presence of invertebrates (in 50% of all brown hyaena scats), suggests that they mainly scavenged. Jackal scats contained a higher proportion of small mammal remains, suggesting that jackals actively hunted more often than brown hyaenas did. The diets differed significantly between the two species, even though diet overlap was fairly high (0.79). Further analysis, albeit based on small sample sizes, suggests that diet of these mesopredators differ between protected reserves with apex predators and unprotected areas without apex predators, thus confounding generalizations. Further studies are therefore required to investigate possible mesopredator release when apex predators are absent
Macroscopic authentication of Chinese materia medica (CMM): A UK market study of seeds and fruits
This small-scale macroscopic and quantitative authentication study, the first of its kind in the UK and elsewhere, assesses the identity and purity (excluding pesticides and heavy metals) of a selection of Chinese materia medica (CMM) seeds and fruits on the UK market. 25 fruit and seed CMM were chosen based on their inclusion in the Chinese Pharmacopoeia (2010, referred hereafter as ‘official species’), maximum dimension of 10 mm, and regular use in Traditional Chinese Medicine (TCM) practice in the UK according to UK practitioners. In 2012 samples were obtained from six TCM wholesale traders and eight retail dispensaries in southeast England. Macroscopic identity and purity testing was undertaken drawing on expertise at the Royal Botanic Gardens, Kew and its collection of vouchered CMM reference drugs, herbarium specimens and published identification texts. Of the 25 CMM requested from suppliers, 23 were obtained, represented by 211 samples. 191 samples were identified as being sourced from the correct drug; 20 were identified as sourced from unofficial species. Of the 191 correct samples, 5 displayed major contamination by other plant material, stones, earth, etc. (defined as > 5% of sample volume), and 12 had minor contamination (2–5%). 95% of samples derived from medicinally cultivated plants were sourced from an official species, 5% were contaminated; in contrast, 78% of wild-sourced CMM samples were sourced from an official species, and 14% showed contamination. These results aim to guide the further development of good practice in TCM herbal drug quality control, for which suggestions are provided
Long-term changes in soil microbial communities during primary succession
Soil microbial communities (SMCs) play a critical role in the cycling of carbon and nutrients in
terrestrial ecosystems, as well as regulating plant productivity and diversity. However, very
little is known about long-term (decades-centuries) structural changes in these communities.
The development of aboveground-belowground linkages during century-scale succession is
also poorly understood. Our study addressed this knowledge gap by investigating SMC and
plant communities undergoing primary succession on an 850-year chronosequence of lava
flows in Iceland. We hypothesised that communities of microfungi and bacteria would
respond to progressive changes in vegetation and that SMC diversity would increase with
terrain age. Soil samples were collected from three lava flows at different stages of primary
succession (165, 621 and 852 years after lava flow emplacement). Plant community
composition was surveyed as the samples were collected. The composition of the SMCs
present in the soil was determined using amplicon pyrosequencing. The physical and
chemical properties of the soil were also analysed. The results of the study indicated
changes in plant and fungal communities with increasing terrain age. Distinct plant and
fungal assemblages were identified on the three sites and both communities became richer
and more diverse with increasing terrain age. There was also evidence to suggest the
development of mycorrhizal associations on older sites. In contrast, the composition and
structure of the bacterial communities did not change systematically with terrain age.
Similarly, there were few changes in soil properties: SOM concentrations and pH, both of
which have been demonstrated to be important to SMCs, were constant across the
chronosequence. These results suggest that plant community composition is significant for
fungal communities, but less relevant for bacterial communities. This finding has implications
for studies of primary succession and the biogeochemical impact of vegetation change in
high-latitude ecosystems.This work was funded by a
Small Ecological Project Grant from the British Ecological Society (grant number 2812/3507)
and grants from the John Fell Fund, University of Oxford (grant number 091/148) and Trinity
College, University of Cambridge.This is the accepted manuscript. The final version is available at http://www.sciencedirect.com/science/article/pii/S003807171300429X
Boekbespreking
Landman, C & Whitelaw, DP (red) 1985 - Windows on origins / Oorspronge in oënskou: Opstelle oor die vroeë kerk ter ere van JAAA Stoop op sy sestigste verjaarsdagPretoria: Universiteit van Suid-Afrika. 102 bladsye. Prys R24 plus AVBBalke, W 1985 - Calvin und die Taufer: Evangelium oder religioser Humanismus. Ubersetzt von H Quistorp Minden - Westfalia Selbstverlag Pfr Dr HJJ Th Quistorp. 292 bladsye. Prys onbekend.Vorster, WS (red) 1985 - Views on violencePretoria: University of South Africa. 118 bladsye. Hardeband. Prys R13,00 plus AVB.Instituut vir Reformatoriese Studies, 1985 - Venster op die Onderwys. (Reeks nr S 3. Versamelwerke nr 24)Potchefstroom: PU vir CHO. 147 bladsye. Prys R7,00. 16 hoofstukke deur verskeie medewerkers
Evaluation of coagulation activation after Rhinovirus infection in patients with asthma and healthy control subjects: an observational study
Background Asthma exacerbations are frequently triggered by rhinovirus infections. Both asthma and respiratory tract infection can activate haemostasis. Therefore we hypothesized that experimental rhinovirus-16 infection and asthmatic airway inflammation act in synergy on the haemostatic balance. Methods 28 patients (14 patients with mild allergic asthma and 14 healthy non-allergic controls) were infected with low-dose rhinovirus type 16. Venous plasma and bronchoalveolar lavage fluid (BAL fluid) were obtained before and 6 days after infection to evaluate markers of coagulation activation, thrombin-antithrombin complexes, von Willebrand factor, plasmin-antiplasmin complexes, plasminogen activator inhibitor type-1, endogenous thrombin potential and tissue factor-exposing microparticles by fibrin generation test, in plasma and/or BAL fluid. Data were analysed by nonparametric tests (Wilcoxon, Mann Whitney and Spearman correlation). Results 13 patients with mild asthma (6 females, 19-29 y) and 11 healthy controls (10 females, 19-31 y) had a documented Rhinovirus-16 infection. Rhinovirus-16 challenge resulted in a shortening of the fibrin generation test in BAL fluid of asthma patients (t = -1: 706 s vs. t = 6: 498 s; p = 0.02), but not of controls (t = -1: 693 s vs. t = 6: 636 s; p = 0.65). The fold change in tissue factor-exposing microparticles in BAL fluid inversely correlated with the fold changes in eosinophil cationic protein and myeloperoxidase in BAL fluid after virus infection (r = -0.517 and -0.528 resp., both p = 0.01). Rhinovirus-16 challenge led to increased plasminogen activator inhibitor type-1 levels in plasma in patients with asthma (26.0 ng/mL vs. 11.5 ng/mL in healthy controls, p = 0.04). Rhinovirus-16 load in BAL showed a linear correlation with the fold change in endogenous thrombin potential, plasmin-antiplasmin complexes and plasminogen activator inhibitor type-1. Conclusions Experimental rhinovirus infection induces procoagulant changes in the airways of patients with asthma through increased activity of tissue factor-exposing microparticles. These microparticle-associated procoagulant changes are associated with both neutrophilic and eosinophilic inflammation. Systemic activation of haemostasis increases with Rhinoviral load
Botshabelo: Reaksie van 'n tipiese slaapdorp op veranderende sosio-ekonomiese omstandighede in 'n "Nuwe Suid-Afrika“
Research has indicated that changing socio-economic conditions in a “New South Africa” have wide-reaching consequences in a “dormitory town ” such as Botshabelo. The purpose of this article is to determine which changes in respect of demographic and related aspects, as well as in the field of economics, have occurred in Botshabelo over a period of three years. A comparison of data obtained during surveys undertaken in 1988/89 and again in 1991 can throw light on changes which have occurred. As far as the demographic profile of the population is concerned, information was obtained during both the 1988/89 and 1991 surveys on a sample basis by means of personal interviews conducted within the community on the basis of interview schedules. During both surveys economic data was also obtained by means of interviews conducted with various enterprises on the basis of interview schedules. The technique of input-output analysis was employed on both occasions to analyse the local economy. Aspects discussed in the article are estimated population size, factors influencing population growth, such as the composition and size of households, age distribution o f the community, births and mortality, as well as expected future population growth. This is followed by a discussion of the performance of formal enterprises with regard to local sales, value added, import and exogenous demand, as well as of changes with regard to job opportunities and work-place, distribution of the labour force according to sector, the economically active population according to industry, sales and income of households.*This article is written in Afrikaans
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