27 research outputs found
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Synthesis and antiviral properties of spirocyclic [1,2,3]-triazolooxazine nucleosides
An efficient synthesis of spirocyclic triazolooxazine nucleosides is described. This was achieved by the conversion of β-D-psicofuranose to the corresponding azido-derivative, followed by alkylation of the primary alcohol with a range of propargyl bromides - obtained via Sonogashira chemistry. The products of these reactions underwent 1,3-dipolar addition smoothly to generate the protected spirocyclic adducts. These were easily deprotected to give the corresponding ribose nucleosides. The library of compounds obtained was investigated for its antiviral activity, using MHV (Mouse Hepatitis Virus) as a model wherein derivative 3f showed the most promising activity and tolerability
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Synthesis and antiviral activity of novel spirocyclic nucleosides
The synthesis of a number of spirocyclic ribonucleosides containing either a triazolic or azetidinic system is described, along with two analogous phosphonate derivatives of the former. These systems were constructed from the same β-D-psicofuranose starting material. The triazole spirocyclic nucleosides were constructed using the 1-azido-1-hydroxymethyl derived sugars, where the primary alcohol was alkylated with a range of propargyl bromides, whereas the azetidine systems orginated from the corresponding 1-cyano-1-hydroxymethyl sugars. Owing to their close similarity with ribavirin, the library of compounds were investigated for their antiviral properties using MHV (Murine Hepatitis Virus) as a model
Histone H3F3A and HIST1H3B K27M mutations define two subgroups of diffuse intrinsic pontine gliomas with different prognosis and phenotypes
Assessing Recovery from the 2004 Indian Ocean Tsunami: An Application of Night-time Light Data and Vegetation Index
It has been 10 years since the Indian Ocean Tsunami caused serious damage to the coastal areas in South and Southeast Asia. The effects on vegetation and human settlements in the affected areas were enormous. This study presents the results of an analysis estimating the long-term recovery using two longitudinal remotely sensed dataset: 1. Moderate Resolution Imaging Spectroradiometer enhanced vegetation index (MODIS EVI), a dataset accounting for change in the landscape and vegetation; and 2. Defense Meteorological Satellite Program-Optical Line Scanner (DMSP-OLS) night-time light data in order to estimate the effects on human and economic activities. It is evident from the results of this study that the night-time light and vegetation index datasets can both be beneficial in identifying changes caused by natural disasters and can be used to track recovery. The results using night-time light indicates a large loss of lighted area but also a rapid recovery of night-time light after the tsunami. Already in year 2005-2006, the levels of lighted area and sum of the lighting (SOL) intensity reached the same levels as pre-tsunami. For MODIS vegetation index, a drop can be observed in 2005/2006 on locations close to the coastline using 1 year temporal resolution; however, when utilizing the 16 day temporal resolution, the impact of the tsunami is illustrated as a dramatic drop, mostly in pixels located within 3km from the coast. Following the drop in vegetation index due to the tsunami, it was observed that most pixels exhibited at least some level of recovery in 2 years after the event