Showing 20245–20258 of 21,218 results for "Satyam Sahu"

Journals 2018 EN

Parallel strategies for the synthesis of annulated pyrido[3,4-b]indoles via Rh(I)- and Pd(0)-catalyzed cyclotrimerization

Bianca M. Saliba · Satyam Khanal · Michael A. O’Donnell +4 more

Two different pathways for the synthesis of annulated pyrido[3,4- b ]indoles are reported using metal-catalyzed cyclotrimerization reactions. A stepwise process using Rh(I)-catalysis in the final step of the synthesis and a multicomponent, tandem catalytic approach using Pd(0)-catalysis both lead to complex nitrogen-containing heterocycles in good yields. Substituent effects are investigated for both pathways, demonstrating that the Pd(0)-catalyzed approach is more sensitive to electron- withdrawing groups.

Elsevier BV
Journals 2018 EN

Quality of service aware multicasting in heterogeneous vehicular networks

Mehdi Sharifi Rayeni · Abdelhakim Hafid · Pratap Kumar Sahu

Heterogeneous Vehicular Networks (HetVNets) provide great potential for on-demand services. Such services require real-time request-reply routing between vehicles as clients and service providers as the source. One naive solution to deliver service is unicasting between service provider and each client. Unicasting consumes considerable bandwidth, since service provider requires establishing a separate communication path to each client. In contrast, the service provider can construct a multicast tree to simultaneously transmit multicast packets to all clients. We propose two approaches to model total bandwidth usage of a multicast tree: (1) Min Steiner Tree that considers the number of street segments involved in the multicast tree; and (2) Min Relay Intersections Tree that considers the number of intersections involved in the multicast tree. We propose a heuristic that incorporates the first approach to minimize delay of the multicast tree. We propose another heuristic that uses the second approach to minimize the number of relay intersections in the multicast tree. Extensive simulations show that the proposed approaches outperform existing contributions in terms of number of transmissions, delivery delay, packet delivery ratio, and overhead. We also show that the proposed approaches near-optimally minimize bandwidth usage while ensuring QoS (i.e. network connectivity and packet transmission delay).

Elsevier BV
Journals 2018 EN

Assigning methyl resonances for protein solution-state NMR studies

Scott D. Gorman · Debashish Sahu · Kathleen F. O’Rourke +1 more

Solution-state NMR is an important tool for studying protein structure and function. The ability to probe methyl groups has substantially expanded the scope of proteins accessible by NMR spectroscopy, including facilitating study of proteins and complexes greater than 100 kDa in size. While the toolset for studying protein structure and dynamics by NMR continues to grow, a major rate-limiting step in these studies is the initial resonance assignments, especially for larger (>50 kDa) proteins. In this practical review, we present strategies to efficiently isotopically label proteins, delineate NMR pulse sequences that can be used to determine methyl resonance assignments in the presence and absence of backbone assignments, and outline computational methods for NMR data analysis. We use our experiences from assigning methyl resonances for the aromatic biosynthetic enzymes tryptophan synthase and chorismate mutase to provide advice for all stages of experimental set-up and data analysis.

Elsevier BV
Journals 2018 EN

Albiglutide and cardiovascular outcomes in patients with type 2 diabetes and cardiovascular disease (Harmony Outcomes): a double-blind, randomised placebo-controlled trial

Adrian F. Hernandez · Jennifer B. Green · Salim Janmohamed +793 more

Glucagon-like peptide 1 receptor agonists differ in chemical structure, duration of action, and in their effects on clinical outcomes. The cardiovascular effects of once-weekly albiglutide in type 2 diabetes are unknown. We aimed to determine the safety and efficacy of albiglutide in preventing cardiovascular death, myocardial infarction, or stroke.

Elsevier BV
Journals 2018 EN

Clinical efficacy and safety of a light mask for prevention of dark adaptation in treating and preventing progression of early diabetic macular oedema at 24 months (CLEOPATRA): a multicentre, phase 3, randomised controlled trial

Sobha Sivaprasad · Joana C. Vasconcelos · A Toby Prevost +44 more

We aimed to assess 24-month outcomes of wearing an organic light-emitting sleep mask as an intervention to treat and prevent progression of non-central diabetic macular oedema.

Elsevier BV
Journals 2018 EN

Divergent trends in ischaemic heart disease and stroke mortality in India from 2000 to 2015: a nationally representative mortality study

Calvin Ke · Rajeev Gupta · Denis Xavier +32 more

India accounts for about a fifth of cardiovascular deaths globally, but nationally representative data on mortality trends are not yet available. In this nationwide mortality study, we aimed to assess the trends in ischaemic heart disease and stroke mortality over 15 years using the Million Death Study.

Elsevier BV
Journals 2018 EN

Interaction of droplet dispersion and evaporation in a polydispersed spray

Srikrishna Sahu · Yannis Hardalupas · A. M. K. P. Taylor

The interaction between droplet dispersion and evaporation in an acetone spray evaporating under ambient conditions is experimentally studied with an aim to understand the physics behind the spatial correlation between the local vapour mass fraction and droplets. The influence of gas-phase turbulence and droplet–gas slip velocity of such correlations is examined, while the focus is on the consequence of droplet clustering on collective evaporation of droplet clouds. Simultaneous and planar measurements of droplet size, velocity and number density, and vapour mass fraction around the droplets, were obtained by combining the interferometric laser imaging for droplet sizing and planar laser induced fluorescence techniques (Sahu et al., Exp. Fluids, vol. 55, 1673, 2014b, pp. 1–21). Comparison with droplet measurements in a non-evaporating water spray under the same flow conditions showed that droplet evaporation leads to higher fluctuations of droplet number density and velocity relative to the respective mean values. While the mean droplet–gas slip velocity was found to be negligibly small, the vaporization Damköhler number ( $Da_{v}$ ) was approximately ‘one’, which means the droplet evaporation time and the characteristic time scale of large eddies are of the same order. Thus, the influence of the convective effect on droplet evaporation is not expected to be significant in comparison to the instantaneous fluctuations of slip velocity, which refers to the direct effect of turbulence. An overall linearly increasing trend was observed in the scatter plot of the instantaneous values of droplet number density ( $N$ ) and vapour mass fraction ( $Y_{F}$ ). Accordingly, the correlation coefficient of fluctuations of vapour mass fraction and droplet number density ( $R_{n\ast y}$ ) was relatively high ( ${\approx}0.5$ ) implying moderately high correlation. However, considerable spread of the $N$ versus $Y_{F}$ scatter plot along both coordinates demonstrated the influence on droplet evaporation due to turbulent droplet dispersion, which leads to droplet clustering. The presence of droplet clustering was confirmed by the measurement of spatial correlation coefficient of the fluctuations of droplet number density for different size classes ( $R_{n\ast n}$ ) and the radial distribution function (RDF) of the droplets. Also, the tendency of the droplets to form clusters was higher for the acetone spray than the water spray, indicating that droplet evaporation promoted droplet grouping in the spray. The instantaneous group evaporation number ( $G$ ) was evaluated from the measured length scale of droplet clusters (by the RDF) and the average droplet size and spacing in instantaneous clusters. The mean value of $G$ suggests an internal group evaporation mode of the droplet clouds near the spray centre, while single droplet evaporation prevails near the spray boundary. However, the large fluctuations in the magnitude of instantaneous values of $G$ at all measurement locations implied temporal variations in the mode of droplet cloud evaporation.

Cambridge University Press