107 research outputs found
Fire Progression
Fires have grown up to 70% in recent years. Fire Progression is a Machine Learning research project wherein we are trying to predict the direction in which the fire might grow in future. We are using Machine Learning technique and features like surface temperature, air temperature, moisture, precipitation and other additional parameters to predict the progression
Initial Steps of Thermal Decomposition of Dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate Crystals from Quantum Mechanics
Dihydroxylammonium 5,5?-bistetrazole-1,1?-diolate (TKX-50) is a recently synthesized energetic material (EM) with most promising performance, including high energy content, high density, low sensitivity, and low toxicity. TKX-50 forms an ionic crystal in which the unit cell contains two bistetrazole dianions {c-((NO)N3C)-[c-(CN3(NO)], formal charge of ?2} and four hydroxylammonium (NH3OH)+ cations (formal charge of +1). We report here quantum mechanics (QM)-based reaction studies to determine the atomistic reaction mechanisms for the initial decompositions of this system. First we carried out molecular dynamics simulations on the periodic TKX-50 crystal using forces from density functional based tight binding calculations (DFTB-MD), which finds that the chemistry is initiated by proton transfer from the cation to the dianion. Continuous heating of this periodic system leads eventually to dissociation of the protonated or diprotonated bistetrazole to release N2 and N2O. To refine the mechanisms observed in the periodic DFTB-MD, we carried out finite cluster quantum mechanics studies (B3LYP) for the unimolecular decomposition of the bistetrazole. We find that for the bistetrazole dianion, the reaction barrier for release of N2 is 45.1 kcal/mol, while release of N2O is 72.2 kcal/mol. However, transferring one proton to the bistetrazole dianion decreases the reaction barriers to 37.2 kcal/mol for N2 release and 59.5 kcal/mol for N2O release. Thus, we predict that the initial decompositions in TKX-50 lead to N2 release, which in turn provides the energy to drive further decompositions. On the basis of this mechanism, we suggest changes to make the system less sensitive while retaining the large energy release. This may help improve the synthesis strategy of developing high nitrogen explosives with further improved performance
Protective effect of <i style="mso-bidi-font-style: normal">Dillenia indica</i> L. on acetic acid induced colitis in mice
876-881The inflammatory bowel disease (IBD) is an idiopathic, immune
mediated and chronic inflammation of the intestine. The study aimed to elucidate the
ameliorative effect of methanolic extract of Dillenia indica (DIME), hexane fraction
(HFDI) and chloroform fraction (CFDI) of Dillenia
indica in acetic acid induced experimental colitis in mice. Macroscopic score,
colon weight, colonic catalase (CAT), superoxide dismutase (SOD), glutathione (GSH),
myeloperoxidase (MPO), malondialdehyde (MDA), tumor necrosis factor (TNF-α), and
histological changes were recorded after the treatment regimen of 7 days. Intra-rectal
instillation of acetic acid caused enhanced macroscopic score, colon weight, colonic
MPO, MDA, and TNF-α level. It caused significant decreased level of CAT, SOD
and GSH. DIME (800 mg/kg), HFDI
(200 mg/kg) and CFDI (200 mg/kg) treatment exhibited significant effect in
lowering macroscopic score, colon weight, MPO, MDA, TNF-α levels and elevation
of CAT, GSH and SOD levels. The results suggest that <i style="mso-bidi-font-style:
normal">D. indica has ameliorating effects on experimental colitis by
inhibiting the proinflammatory mediators like TNF-α
production
Large-scale phosphomimetic screening identifies phospho-modulated motif-based protein interactions.
Phosphorylation is a ubiquitous post-translation modification that regulates protein function by promoting, inhibiting or modulating protein-protein interactions. Hundreds of thousands of phosphosites have been identified but the vast majority have not been functionally characterised and it remains a challenge to decipher phosphorylation events modulating interactions. We generated a phosphomimetic proteomic peptide-phage display library to screen for phosphosites that modulate short linear motif-based interactions. The peptidome covers ~13,500 phospho-serine/threonine sites found in the intrinsically disordered regions of the human proteome. Each phosphosite is represented as wild-type and phosphomimetic variant. We screened 71 protein domains to identify 248 phosphosites that modulate motif-mediated interactions. Affinity measurements confirmed the phospho-modulation of 14 out of 18 tested interactions. We performed a detailed follow-up on a phospho-dependent interaction between clathrin and the mitotic spindle protein hepatoma-upregulated protein (HURP), demonstrating the essentiality of the phospho-dependency to the mitotic function of HURP. Structural characterisation of the clathrin-HURP complex elucidated the molecular basis for the phospho-dependency. Our work showcases the power of phosphomimetic ProP-PD to discover novel phospho-modulated interactions required for cellular function
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