248 research outputs found

    Nature Of Transition Circumstellar Disks. I. The Ophiuchus Molecular Cloud

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    We have obtained millimeter-wavelength photometry, high-resolution optical spectroscopy, and adaptive optics near-infrared imaging for a sample of 26 Spitzer-selected transition circumstellar disks. All of our targets are located in the Ophiuchus molecular cloud (d similar to 125 pc) and have spectral energy distributions (SEDs) suggesting the presence of inner opacity holes. We use these ground-based data to estimate the disk mass, multiplicity, and accretion rate for each object in our sample in order to investigate the mechanisms potentially responsible for their inner holes. We find that transition disks are a heterogeneous group of objects, with disk masses ranging from <0.6 to 40 M(JUP) and accretion rates ranging from <10(-11) to 10(-7) M(circle dot) yr(-1), but most tend to have much lower masses and accretion rates than "full disks" (i.e., disks without opacity holes). Eight of our targets have stellar companions: six of them are binaries and the other two are triple systems. In four cases, the stellar companions are close enough to suspect they are responsible for the inferred inner holes. We find that nine of our 26 targets have low disk mass (<2.5 M(JUP)) and negligible accretion (<10(-11) M(circle dot) yr(-1)), and are thus consistent with photoevaporating (or photoevaporated) disks. Four of these nine non-accreting objects have fractional disk luminosities <10(-3) and could already be in a debris disk stage. Seventeen of our transition disks are accreting. Thirteen of these accreting objects are consistent with grain growth. The remaining four accreting objects have SEDs suggesting the presence of sharp inner holes, and thus are excellent candidates for harboring giant planets.NASA 1224608, 1230782, 1230779, 1407FONDECYT 1061199Basal CATA PFB 06/09ALMA FUND 31070021ALMA-Conicyt FUND 31060010National Science Foundation AST0-808144Spitzer Space Telescope Legacy Science ProgramAstronom

    Prescription pattern of NSAIDS and the prevalence of NSAID-induced gastrointestinal risk factors of orthopaedic patients

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    Background: Nonsteroidal anti-inflammatory drugs (NSAIDs) are one of the most commonly used medications in the world. NSAID-induced adverse reactions involve upper gastrointestinal (GI) tract complications, which can be life-threatening. Objectives: The study was conducted to explore the current prescription pattern of non-steroidal anti-inflammatory drugs (NSAIDs) and the prevalence of NSAID-induced gastrointestinal(GI) risk factors of orthopedic adult inpatient.Materials and methods: A prospective observational NSAIDs induced GI risk related study was conducted over a period of 6 months by clinical pharmacist. Study cohort included 105 orthopaedic inpatients who are taking or will be taking NSAIDs for more than a week. A self-administered questionnaire was completed by each patient. A simplified risk scoring scale (the Standardized Calculator of Risk for Events; SCORE) was used to measure patients‟ risk for GI complications. The pattern of NSAIDs prescription was identified from medical recordings.Results: The study groups were stratified into four risk groups according to GI SCORE tool, 27.6% of the patients belonged to high risk or very high risk groups for GI complications. Analysis of prescription pattern revealed that 11.4% of the patients aged over 65 yr, 19% with co morbid disease were prescribed with COX-2 selective inhibitor. Conclusion: In this study assessment of prescription pattern and GI risk factors for NSAIDs were evaluated and in conclusion, physician‟s considerate prescription of NSAIDs with well-understanding of each patient‟s GI risk factors is strongly encouraged to prevent serious GI complication

    Identification of Artocarpus hirsutus and Garcinia gummi-gutta as the sources of trypsin inhibitory proteins

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    Natural trypsin inhibitors from plant tissues are emerging with promising therapeutic uses. They have profound applications in medicine and biotechnology and are extensively used in the food and medicine industry. Their activities are affected by detergents, metal ions, and reducing or chelating agents that are commonly used in these industries. Artocarpus hirsutus and Garcinia gummi-gutta are two tropical trees wherein most of the plant parts except the seeds were extensively studied and proved to possess medicinal properties. In the present study, the seeds of these tropical plants are proved to possess trypsin inhibitory activity. We report here the partial purification of trypsin inhibitory proteins from mature seed extracts of A. hirsutus and G.gummi-gutta in 50 mM phosphate buffer (pH 7.6). The partial purification was done by ammonium sulphate precipitation. Modulation of activity of A. hirsutus and G. gummi-gutta TIs by thermal stabilisers, metal ions and detergents were analysed. There was a significant fold of purification, in both cases. The thermal stabilisers, metal ions and detergents modulate the activities of the two TIs in their way. The study effectively provides choices of optimal additives to be used, where industrial processing of these TIs is required for therapeutic applications

    Deciduous Tundra Shrubs Shift Toward More Acquisitive Light Absorption Strategy Under Climate Change Treatments

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    The effects of climate change on plants are particularly pronounced in the Arctic region. Warming relaxes the temperature and nutrients boundaries that limit tundra plant growth. Increased resource availability under future climate conditions may induce a shift from a conservative economic strategy to an acquisitive one. Following the leaf economics spectrum that hypothesizes a strategy gradient between survival, plant size and costs for the photosynthetic leaf area, light absorption of tundra plants may increase. We investigated climate change effects on light absorptance and the relationship between light absorptance (fraction of absorbed photosynthetically active radiation, FAPAR) and structural and nutritional leaf traits, performing a soil warming and surface soil fertilization experiment on two deciduous tundra shrub species. Our results show that fertilization and warming combined increase light absorptance in Arctic shrubs and that FAPAR is correlated with leaf nutrients but not with structural leaf traits. This indicates an economic strategy shift of shrubs from conservative to acquisitive induced by warming and fertilization combined. We found species‐specific differences: FAPAR was influenced by warming alone in Betula nana but not in Salix pulchra, and FAPAR was correlated with leaf phosphorus in B. nana but not in S. pulchra. We attribute this to water limitation of B. nana that generally grows in drier areas within the study site compared to S. pulchra. We conclude that FAPAR is a measure that opens up more possibilities to estimate nutritional leaf traits and nutrient cycles, plant economic strategies, and ecological feedbacks of the tundra ecosystem on broader scales

    Identification of Artocarpus hirsutus and Garcinia gummi-gutta as the sources of trypsin inhibitory proteins

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    195-201Natural trypsin inhibitors from plant tissues are emerging with promising therapeutic uses. They have profound applications in medicine and biotechnology and are extensively used in the food and medicine industry. Their activities are affected by detergents, metal ions, and reducing or chelating agents that are commonly used in these industries. Artocarpus hirsutus and Garcinia gummi-gutta are two tropical trees wherein most of the plant parts except the seeds were extensively studied and proved to possess medicinal properties. In the present study, the seeds of these tropical plants are proved to possess trypsin inhibitory activity. We report here the partial purification of trypsin inhibitory proteins from mature seed extracts of A. hirsutus and G.gummi-gutta in 50 mM phosphate buffer (pH 7.6). The partial purification was done by ammonium sulphate precipitation. Modulation of activity of A. hirsutus and G. gummi-gutta TIs by thermal stabilisers, metal ions and detergents were analysed. There was a significant fold of purification, in both cases. The thermal stabilisers, metal ions and detergents modulate the activities of the two TIs in their way. The study effectively provides choices of optimal additives to be used, where industrial processing of these TIs is required for therapeutic applications

    The Spatial Distribution of Star Formation in the Solar Neighbourhood: Do all stars form in clusters?

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    We present a global study of low mass, young stellar object (YSO) surface densities in nearby (< 500 pc) star forming regions based on a comprehensive collection of Spitzer Space Telescope surveys. We show that the distribution of YSO surface densities in the solar neighbourhood is a smooth distribution, being adequately described by a lognormal function from a few to 10^3 YSOs per pc^2, with a peak at 22 stars/pc^2 and a dispersion of 0.85. We do not find evidence for multiple discrete modes of star-formation (e.g. clustered and distributed). Comparing the observed surface density distribution to previously reported surface density threshold definitions of clusters, we find that the fraction of stars in clusters is crucially dependent on the adopted definitions, ranging from 40 to 90%. However, we find that only a low fraction (< 26%) of stars are formed in dense environments where their formation/evolution (along with their circumstellar disks and/or planets) may be affected by the close proximity of their low-mass neighbours.Comment: 6 pages, 2 figures, MNRAS letters, accepte

    OPTIMIZATION OF ANNEALING TEMPERATURE FOR COI GENE AMPLIFICATION ON EXTRIMOPHIL FISH USING REAL-TIME PCR

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    Extremophilic fish require genetic characterization to determine the identity of their species, their kinship, and the potential for genetic variation due to extreme environmental adaptation. DNA barcoding using Fish-F2 and Fish-R2 primers at an annealing temperature of 52oC for 15 seconds showed qualitative failure results in most fish species. For this reason, optimizing the annealing temperature in the PCR process is necessary to obtain DNA bands that correlate with successful identification. Fish samples were obtained from Ruai Silip, Bangka Island, Membalong, Belitung Island, and Way Kanan, Lampung, Sumatra Island. The annealing temperature optimization was set at 50, 50.4, 51.1, 52.3, 53.7, 54.8, 55.5, and 56°C. Five species of extremophile fish were tested, namely Brevibora sp, Barbodes binotatus, Rasbora bankanensis, Anabas testudineus, and Aplocheilus panchax. Extremophile fish showed differences in the appearance of DNA bands in PCR with different annealing temperatures. Brevibora sp showed a visualization of DNA bands at 54.8°C, Barbodes binotatus at 53.7, 54.8, 55.5, and 56°C, Anabas testudineus at 50 and 50.4°C, and Aplocheilus panchax produced clearly visible band on annealing temperatures

    The Rapid Outbursting Star GM Cep: An EX-or in Tr 37?

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    We present optical, IR and millimeter observations of the solar-type star 13-277, also known as GM Cep, in the 4 Myr-old cluster Tr 37. GM Cep experiences rapid magnitude variations of more than 2 mag at optical wavelengths. We explore the causes of the variability, which seem to be dominated by strong increases in the accretion, being similar to EX-or episodes. The star shows high, variable accretion rates (up to ~106^{-6} Msun/yr), signs of powerful winds, and it is a very fast rotator (Vsini~43 km/s). Its strong mid-IR excesses reveal a very flared disk and/or a remnant envelope, most likely out of hydrostatic equilibrium. The 1.3 millimeter fluxes suggest a relatively massive disk (Mdisk~0.1 Msun). Nevertheless, the millimeter mass is not enough to sustain increased accretion episodes over large timescales, unless the mass is underestimated due to significant grain growth. We finally explore the possibility of GM Cep having a binary companion, which could trigger disk instabilities producing the enhanced accretion episodes.Comment: 43 pages, including 10 figures, ApJ in pres
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