4,850 research outputs found

    Tagetes spp. Essential oils and other extracts : chemical characterization and biological activity

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    Tagetes (marigold) is native to America, and its cultivation currently extends to other countries in Africa, Asia, and Europe. Many species of this genus, such as T. minuta, T. erecta, T. patula, and T. tenuifolia, are cultivated as ornamental plants and studied for their medicinal properties on the basis of their use in folk medicine. Different parts of the Tagetes species are used as remedies to treat various health problems, including dental, stomach, intestinal, emotional, and nervous disorders, as well as muscular pain, across the world. Furthermore, these plants are studied in the field of agriculture for their fungicidal, bactericidal, and insecticidal activities. The phytochemical composition of the extracts of different Tagetes species parts are reported in this work. These compounds exhibit antioxidant, antiinflammatory, and enzyme inhibitory properties. Cultivation and the factors affecting the chemical composition of Tagetes species are also covered. In the current work, available literature on Tagetes species in traditional medicine, their application as a food preservative, and their antimicrobial activities are reviewed

    Accreting Neutron Stars in Low-Mass X-Ray Binary Systems

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    Using the Rossi X-ray Timing Explorer (RossiXTE), astronomers have discovered that disk-accreting neutron stars with weak magnetic fields produce three distinct types of high-frequency X-ray oscillations. These oscillations are powered by release of the binding energy of matter falling into the strong gravitational field of the star or by the sudden nuclear burning of matter that has accumulated in the outermost layers of the star. The frequencies of the oscillations reflect the orbital frequencies of gas deep in the gravitational field of the star and/or the spin frequency of the star. These oscillations can therefore be used to explore fundamental physics, such as strong-field gravity and the properties of matter under extreme conditions, and important astrophysical questions, such as the formation and evolution of millisecond pulsars. Observations using RossiXTE have shown that some two dozen neutron stars in low-mass X-ray binary systems have the spin rates and magnetic fields required to become millisecond radio-emitting pulsars when accretion ceases, but that few have spin rates above about 600 Hz. The properties of these stars show that the paucity of spin rates greater than 600 Hz is due in part to the magnetic braking component of the accretion torque and to the limited amount of angular momentum that can be accreted in such systems. Further study will show whether braking by gravitational radiation is also a factor. Analysis of the kilohertz oscillations has provided the first evidence for the existence of the innermost stable circular orbit around dense relativistic stars that is predicted by strong-field general relativity. It has also greatly narrowed the possible descriptions of ultradense matter.Comment: 22 pages, 7 figures, updated list of sources and references, to appear in "Short-period Binary Stars: Observation, Analyses, and Results", eds. E.F. Milone, D.A. Leahy, and D. Hobill (Dordrecht: Springer, http://www.springerlink.com

    First report on methicillin-resistant Staphylococcus aureus of Spa type T037, Sequence type 239, SCCmec type III/IIIA in Malaysia

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    Methicillin-resistant Staphylococcus aureus (MRSA) from Malaysia were shown to possess staphylococcal cassette chromosome mec (SCCmec)-III and IIIA. Spa sequencing and multi-locus sequence typing (MLST) documented t037 and ST 239 (CC8) for 83.3% of the isolates. This confirms observations in several other Far Eastern countries and corroborates the epidemicity of this clone
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