145 research outputs found

    Studies on adsorption of surfactants on solid-liquid interface and its importance in slurry-rheology

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    The knowledge of rheological properties for different materials for slurry preparation is of great importance. These topics are studied and severely important for several technical applications e.g. process control in chemical engineering, casting of ceramics, storage, transport of solids in pipelines and atomization. A literature on the change in rheological properties of coal water slurry is reviewed. The adsorption effect of surfactants like cationic, anionic and nonionic on the solid liquid interface is investigated. The rheological behaviors of kaolin-water slurry are experimented by using a rotational viscometer (Brookfield syncrolacto viscometer) with different solid concentrations. These experiments are conducted under a particular speed (in rpm) of the spindle, temperature and ph condition. The adsorption kinetics for the three different surfactants at their CMC values is studied for different amount of kaolin (in wt %) using a UV spectrophotometer. The cause of change in viscosity is investigated with the out coming results of the experiments and found that cationic and anionic surfactants affect the kaolin-water slurry rheology severel

    Cytochromeâ P450â Induced Ordering of Microsomal Membranes Modulates Affinity for Drugs

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    Although membrane environment is known to boost drug metabolism by mammalian cytochromeâ P450s, the factors that stabilize the structural folding and enhance protein function are unclear. In this study, we use peptideâ based lipid nanodiscs to â trapâ the lipid boundaries of microsomal cytochromeâ P450 2B4. We report the first evidence that CYP2B4 is able to induce the formation of raft domains in a biomimetic compound of the endoplasmic reticulum. NMR experiments were used to identify and quantitatively determine the lipids present in nanodiscs. A combination of biophysical experiments and molecular dynamics simulations revealed a sphingomyelin binding region in CYP2B4. The proteinâ induced lipid raft formation increased the thermal stability of P450 and dramatically altered ligand binding kinetics of the hydrophilic ligand BHT. These results unveil membrane/protein dynamics that contribute to the delicate mechanism of redox catalysis in lipid membrane.Redox catalysis in the lipid membrane: A novel application of peptide nanodiscs shows that cytochromeâ P450 2B4 is able to induce the formation of lipid raft domains in a biomimetic compound of the endoplasmic reticulum (ER). The proteinâ induced lipid rafts increase the thermal stability cytochromeâ P450 and dramatically alter the ligandâ binding kinetics of the hydrophilic ligand BHT.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142960/1/anie201713167.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142960/2/anie201713167_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142960/3/anie201713167-sup-0001-misc_information.pd

    Azimuthal anisotropy of charged jet production in root s(NN)=2.76 TeV Pb-Pb collisions

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    We present measurements of the azimuthal dependence of charged jet production in central and semi-central root s(NN) = 2.76 TeV Pb-Pb collisions with respect to the second harmonic event plane, quantified as nu(ch)(2) (jet). Jet finding is performed employing the anti-k(T) algorithm with a resolution parameter R = 0.2 using charged tracks from the ALICE tracking system. The contribution of the azimuthal anisotropy of the underlying event is taken into account event-by-event. The remaining (statistical) region-to-region fluctuations are removed on an ensemble basis by unfolding the jet spectra for different event plane orientations independently. Significant non-zero nu(ch)(2) (jet) is observed in semi-central collisions (30-50% centrality) for 20 <p(T)(ch) (jet) <90 GeV/c. The azimuthal dependence of the charged jet production is similar to the dependence observed for jets comprising both charged and neutral fragments, and compatible with measurements of the nu(2) of single charged particles at high p(T). Good agreement between the data and predictions from JEWEL, an event generator simulating parton shower evolution in the presence of a dense QCD medium, is found in semi-central collisions. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe

    Forward-central two-particle correlations in p-Pb collisions at root s(NN)=5.02 TeV

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    Two-particle angular correlations between trigger particles in the forward pseudorapidity range (2.5 2GeV/c. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B. V.Peer reviewe

    Event-shape engineering for inclusive spectra and elliptic flow in Pb-Pb collisions at root(NN)-N-S=2.76 TeV

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    Pseudorapidity and transverse-momentum distributions of charged particles in proton-proton collisions at root s=13 TeV

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    The pseudorapidity (eta) and transverse-momentum (p(T)) distributions of charged particles produced in proton-proton collisions are measured at the centre-of-mass energy root s = 13 TeV. The pseudorapidity distribution in vertical bar eta vertical bar <1.8 is reported for inelastic events and for events with at least one charged particle in vertical bar eta vertical bar <1. The pseudorapidity density of charged particles produced in the pseudorapidity region vertical bar eta vertical bar <0.5 is 5.31 +/- 0.18 and 6.46 +/- 0.19 for the two event classes, respectively. The transverse-momentum distribution of charged particles is measured in the range 0.15 <p(T) <20 GeV/c and vertical bar eta vertical bar <0.8 for events with at least one charged particle in vertical bar eta vertical bar <1. The evolution of the transverse momentum spectra of charged particles is also investigated as a function of event multiplicity. The results are compared with calculations from PYTHIA and EPOS Monte Carlo generators. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe

    Elliptic flow of muons from heavy-flavour hadron decays at forward rapidity in Pb-Pb collisions at root s(NN)=2.76TeV

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    The elliptic flow, v(2), of muons from heavy-flavour hadron decays at forward rapidity (2.5 <y <4) is measured in Pb-Pb collisions at root s(NN)= 2.76TeVwith the ALICE detector at the LHC. The scalar product, two- and four-particle Q cumulants and Lee-Yang zeros methods are used. The dependence of the v(2) of muons from heavy-flavour hadron decays on the collision centrality, in the range 0-40%, and on transverse momentum, p(T), is studied in the interval 3 <p(T)<10 GeV/c. A positive v(2) is observed with the scalar product and two-particle Q cumulants in semi-central collisions (10-20% and 20-40% centrality classes) for the p(T) interval from 3 to about 5GeV/c with a significance larger than 3 sigma, based on the combination of statistical and systematic uncertainties. The v(2) magnitude tends to decrease towards more central collisions and with increasing pT. It becomes compatible with zero in the interval 6 <p(T)<10 GeV/c. The results are compared to models describing the interaction of heavy quarks and open heavy-flavour hadrons with the high-density medium formed in high-energy heavy-ion collisions. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V.Peer reviewe

    Centrality evolution of the charged-particle pseudorapidity density over a broad pseudorapidity range in Pb-Pb collisions at root s(NN)=2.76TeV

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    Host Cell Responses to Zika Virus Infection

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    The re-emergence of Zika virus (ZIKV) in 2015 as a significant human pathogen causing neurological diseases in infants as well as adults is a serious global health concern. A clear understanding of the mechanisms involved in ZIKV replication in infected host cells as well as the host responses to virus infection are keys to the development of therapeutic strategies against ZIKV. Studies conducted in this dissertation demonstrate that ZIKV infection induces the activation of mTOR signaling cascade that promotes viral protein accumulation and infectious progeny production. While both mTORC1 and mTORC2 are essential for ZIKV replication, the observation that depletion of Raptor, the unique component of mTORC1, imposes a robust negative effect on ZIKV protein expression and progeny production also suggests a mTOR- independent role played by Raptor. Additionally, the activation of autophagy at early times of infection indicates an antiviral role for autophagy in ZIKV infection. The observation that pharmacological inhibition of autophagy led to increased accumulation of ZIKV proteins further strengthens this contention. Since infection-induced oxidative stress contributes to ZIKV pathogenesis, studies reported in this dissertation also show that ZIKV infection alters the redox homeostasis in infected cells and triggers Nrf2- mediated antioxidant response. Depletion of Nrf2 downregulates the cellular pool of GSHand NADPH leading to enhanced ZIKV replication thereby underscores a role for cellular antioxidants in the suppression of ZIKV replication. The dependency of ZIKV replication on host cell glycolysis is highlighted by significant reduction in viral protein expression and virus yield due to pharmacologic inhibition. When glycolysis is inhibited, gluconeogenesis was found to facilitate ZIKV replication by compensating carbon input via oxidative mitochondrial metabolism. Further experimentation comparing the metabolic profiles of mock- and ZIKV-infected cells may provide important information in understanding the role of cellular metabolism in virus replication
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