446 research outputs found

    Anti-inflammatory and analgesic activities: Chemical constituents of essential oils of Ocimum gratissimum, Eucalyptus citriodora and Cymbopogon giganteus inhibited lipoxygenase L-1 and cyclooxygenase of PGHS

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    The following studies report the inhibitory effect produced by chemical constituents of essential oils of three plants used in traditional medicine as anti-inflammatory and analgesic drugs, in vitro, on soybean lipoxygenase L-1 and cyclooxygenase function of prostaglandin H synthase (PGHS), the two enzymes involved in the production of mediators of inflammation. The essential oils were extracted from plants of three families: O. gratissimum (Labiatae), C. giganteus (Poaceae), and E. citriodora (Myrtaceae). Their chemical composition was established by GC/MS analyses. Among the three essential oils, one showed evident inhibition of L-1 with IC50 value of 72 µg/mL for Eucalyptus citriodora. Only one essential oil that of O. gratissimum inhibited the two enzymes, cyclooxygenase function of PGHS and lipoxygenase L-1, with an IC50 values, respectively, of 125 µg/mL and 144 µg/mL, whereas that of C. giganteus and E. citriodora, two of them had no effect on cyclooxygenase. KEY WORDS: Essential oils, Soybean lipoxygenase (L-1), Cyclooxygenase function ofprostaglandine H synthase-1, PGHS, O. gratissimum (Labiatae), C. giganteus (Poaceae), E. citriodora (Myrtaceae), Enantia chlorantha, Inhibition  Bull. Chem. Soc. Ethiop. 2003, 17(2), 191-197

    Three-dimensional orbits of the triple-O stellar system HD 150136

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    peer reviewedContext. HD 150136 is a triple hierarchical system and a non-thermal radio emitter. It is formed by an O3-3.5 V + O5.5-6 V close binary and a more distant O6.5-7 V tertiary. So far, only the inner orbital properties have been reliably constrained. Aims. To quantitatively understand the non-thermal emission process, accurate knowledge of the physical and orbital properties of the object is crucial. Here, we aim to investigate the orbital properties of the wide system and to constrain the inclinations of the inner and outer binaries, and with these the absolute masses of the system components. Methods. We used the PIONIER combiner at the Very Large Telescope Interferometer to obtain the very first interferometric measurements of HD 150136. We combined the interferometric observations with new and existing high resolution spectroscopic data to derive the orbital solution of the outer companion in the three-dimensional space. Results. The wide system is clearly resolved by PIONIER, with a projected separation on the plane of the sky of about 9 milli-arcsec. The best-fit orbital period, eccentricity, and inclination are 8.2 yr, 0.73 and 108 degr. We constrain the masses of the three stars of the system to 63 +/- 10, 40 +/- 6, and 33 +/- 12 Msun for the O3-3.5 V, O5.5-6 V and O6.5-7 V components. Conclusions. The dynamical masses agree within errors with the evolutionary masses of the components. Future interferometric and spectroscopic monitoring of HD 150136 should allow one to reduce the uncertainties to a few per cent only and to accurately constrain the distance to the system. This makes HD 150136 an ideal system to quantitatively test evolutionary models of high-mass stars as well as the physics of non-thermal processes occurring in O-type systems

    Comparison of HIV prevalence among antenatal clinic attendees estimated from routine testing and unlinked anonymous testing

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    In 2015, WHO and UNAIDS released new guidance recommending that countries transition from conducting antenatal clinic (ANC) unlinked anonymous testing (ANC-UAT) for tracking HIV prevalence trends among pregnant women to using ANC routine testing (ANC-RT) data, which are more consistent and economic to collect. This transition could pose challenges for distinguishing whether changes in observed prevalence are due to a change in underlying population prevalence or due to a change in the testing approach. We compared the HIV prevalence measured from ANC-UAT and ANC-RT in 15 countries that had both data sources in overlapping years. We used linear mixed-effects model (LMM) to estimate the RT-to-UAT calibration parameter as well as other unobserved quantities. We summarized the results at different levels of aggregation (e.g., country, urban, rural, and province). Based on our analysis, the HIV prevalence measured by ANC-UAT and ANC-RT data are consistent in most countries. Therefore, if large discrepancy is observed between ANC-UAT and ANC-RT at the same location, we recommend that people should be cautious and investigate the reason. For countries that lack information to estimate the calibration parameter, we propose an informative prior distribution of mean 0 and standard deviation 0.2 for the RT-to-UAT calibration parameter

    A comparison of South African national HIV incidence estimates: A critical appraisal of different methods

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    BACKGROUND: The interpretation of HIV prevalence trends is increasingly difficult as antiretroviral treatment programs expand. Reliable HIV incidence estimates are critical to monitoring transmission trends and guiding an effective national response to the epidemic. Methods and FINDINGS: We used a range of methods to estimate HIV incidence in South Africa: (i) an incidence testing algorithm applying the Limiting-Antigen Avidity Assay (LAg-Avidity EIA) in combination with antiretroviral drug and HIV viral load testing; (ii) a modelling technique based on the synthetic cohort principle; and (iii) two dynamic mathematical models, the EPP/Spectrum model package and the Thembisa model. Overall, the different incidence estimation methods were in broad agreement on HIV incidence estimates among persons aged 15-49 years in 2012. The assay-based method produced slightly higher estimates of incidence, 1.72% (95% CI 1.38 - 2.06), compared with the mathematical models, 1.47% (95% CI 1.23 - 1.72) in Thembisa and 1.52% (95% CI 1.43 - 1.62) in EPP/Spectrum, and slightly lower estimates of incidence compared to the synthetic cohort, 1.9% (95% CI 0.8 - 3.1) over the period from 2008 to 2012. Among youth aged 15-24 years, a declining trend in HIV incidence was estimated by all three mathematical estimation methods. CONCLUSIONS: The multi-method comparison showed similar levels and trends in HIV incidence and validated the estimates provided by the assay-based incidence testing algorithm. Our results confirm that South Africa is the country with the largest number of new HIV infections in the world, with about 1 000 new infections occurring each day among adults aged 15-49 years in 2012

    Half-metallic antiferromagnets in thiospinels

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    We have theoretically designed the half-metallic (HM) antiferromagnets (AFMs) in thiospinel systems, Mn(CrV)S4\rm Mn(CrV)S_{4} and Fe0.5Cu0.5(V0.5Ti1.5)S4\rm Fe_{0.5}Cu_{0.5}(V_{0.5}Ti_{1.5})S_{4}, based on the electronic structure studies in the local-spin-density approximation (LSDA). We have also explored electronic and magnetic properties of parent spinel compounds of the above systems; CuV2S4\rm CuV_{2}S_{4} and CuTi2S4\rm CuTi_{2}S_{4} are found to be HM ferromagnets in their cubic spinel structures, while MnCr2S4\rm MnCr_{2}S_{4} is a ferrimagnetic insulator. We have discussed the feasibility of material synthesis of HM-AFM thiospinel systems.Comment: 4 pages, 5 figure

    Simulation Modeling and Metamodeling to Inform National and International HIV Policies for Children and Adolescents

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    Objective and Approach: Computer-based simulation models serve an important purpose in informing HIV care for children and adolescents. We review current model-based approaches to informing pediatric and adolescent HIV estimates and guidelines. // Findings: Clinical disease simulation models and epidemiologic models are used to inform global and regional estimates of numbers of children and adolescents living with HIV and in need of antiretroviral therapy, to develop normative guidelines addressing strategies for diagnosis and treatment of HIV in children, and to forecast future need for pediatric and adolescent antiretroviral therapy formulations and commodities. To improve current model-generated estimates and policy recommendations, better country-level and regional-level data are needed about children living with HIV, as are improved data about survival and treatment outcomes for children with perinatal HIV infection as they age into adolescence and adulthood. In addition, novel metamodeling and value of information methods are being developed to improve the transparency of model methods and results, as well as to allow users to more easily tailor model-based analyses to their own settings. // Conclusions: Substantial progress has been made in using models to estimate the size of the pediatric and adolescent HIV epidemic, to inform the development of guidelines for children and adolescents affected by HIV, and to support targeted implementation of policy recommendations to maximize impact. Ongoing work will address key limitations and further improve these model-based projections
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