A one-pot, microwave-influenced synthesis of diverse small molecules by multicomponent reaction cascades

Small molecule diversity can be achieved in a single synthetic operation from bifunctional substrates in the absence of additives and under the influence of microwaves with complete control of pathway selectivity. The preliminary Ugi four-component coupling products give rise to three structurally distinct scaffolds that are dependent on solvent effects and sterics. 2,5-Diketopiperazines (Type A), 2-azaspiro[4.5]deca-6,9-diene-3,8-diones (Type B), and thiophene-derived Diels-Alder tricyclic lactams (Type C) predominate in this reaction cascade.     

Robust reliable sampled-data control for offshore steel jacket platforms with nonlinear perturbations

In this article, we consider the robust reliable sample-data control problem for an offshore steel jacket platform with input time-varying delay and possible occurrence of actuator faults subject to nonlinear self-exited hydrodynamic forces. The main objective of this work is to design a state feedback reliable sample-data controller such that for all admissible uncertainties as well as actuator failure cases, the resulting closed-loop system is robustly exponentially stable. By constructing an appropriate Lyapunov–Krasovskii functional and using linear matrix inequality (LMI) approach, a new set of sufficient condition is derived in terms of LMIs for the existence of robust reliable sample-data control law. In particular, the uncertainty under consideration in system parameters includes linear fractional norm-bounded uncertainty. Further, Schur complement and Jenson’s integral inequality are used to substantially simplify the derivation in the main results. More precisely, the controller gain matrix for the nonlinear offshore steel jacket platform can be achieved by solving the LMIs, which can be easily facilitated by using some standard numerical packages. Finally, a numerical example with simulation result is provided to illustrate the applicability and effectiveness of the proposed reliable sampled-data control scheme.     

Assembly of Dipicolinic Acid by Alkali-Metal Cations

Abstract  

Different types of structures of hydrogen-bond assemblies derived from partially deprotonated dipicolinic acid (LH2) molecules having alkali metal cation such as sodium, potassium and cesium are structurally characterised. These self assembled complexes have general formula [M(LH)(LH2)(H₂O) _m ] _n xH₂O {m = 2, 3, n = 1, 2, n, and x = 0, 0.5 M = Na (1); K (2) and Cs(3)}. Sodium complex is a hepta-coordinate mononuclear complex; potassium complex is octa-coordinate complex with dinuclear K₂O₂ type of carboxylate core; whereas the cesium complex is nona-coordinate polymeric complex. All these complexes crystallises in Triclinic, P-1 space group. Sodium complex has a = 6.9003(4) ?; b = 11.1440(6)?; c = 11.2059(5)?; α = 85.695(4)o; β = 82.103(3)o; γ = 87.432(4)o and volume = 850.60(8) ?³ Z = 2; Potassium complex has a = 7.0937(4)?; b = 11.0034(5)?; c = 11.2732(6)?; α = 91.603(3)o; β = 96.088(3)o; γ = 97.207(4)o; volume = 867.29(8) ?³; Z = 1 and cesium complex has a = 7.1410(6)?; b = 11.0625(8)?; c = 12.0667(9)?; α = 96.849(4)o; β = 93.850(4)o; γ = 105.495(4)o; volume = 907.14(12) ?³; Z = 2.     

Critical properties of island perimeters in the flooding transition of stochastic and rotational sandpile models

Critical properties of external perimeters of islands that appear at the flooding transition in the toppling surfaces, defined by the toppling number _Si$S_i$ of each sand column, of stochastic and rotational sandpile models are studied. A set of new critical exponents are estimated by extensive numerical simulation and finite size scaling analysis. The values of the critical exponents are found different for these sandpile models. Several scaling relations among the critical exponents and the Hurst exponent describing the self-affinity of the toppling surfaces are established and verified. The critical exponents obtained here are also found connected to the exponents describing the avalanche size distribution.     

SEMEDS: an important tool for air pollution bio-monitoring

Plant canopies act as absorbers of air-borne dust particles. Characterization of the dusts present over the leaf surfaces can indicate the nature of contaminant present in the surrounding area and possible sources as well. Dust particulates get adsorbed on both the surfaces of leaves, however more dust particulates get deposited on the upper surface. These dusts contain many inorganic elements, which were analyzed in the present study. For the present investigation, SEMEDS technique used to characterize the dusts adsorbed over the leaf surfaces. Using SEMEDS the samples were analyzed by two types of methods i.e. point analysis and elemental mapping. Both the methods showed the presence of elements like Si, Al, Fe, Mg, and Ca in the dusts adsorbed over the leaf surfaces. Thus, SEMEDS can be used for in situ air pollution monitoring using tree leaves from the area concerned.     

Role of many-electron dynamics in high harmonic generation

High harmonic generation (HHG) in many-electron atoms is studied theoretically. The breakdown of the frozen-core single active electron approximation is demonstrated, as it predicts roughly the same radiation amplitude in all noble gases. This is in contradiction with experiments, where heavier noble gases are known to emit much stronger HHG radiation than lighter ones. This experimental behavior of the noble gases can be qualitatively reproduced when many-electron dynamics, within a simple approximation, is taken into account.     

Random walk on topologically biased anisotropic percolation clusters and transport properties

Unbiased random walks are performed on topologically biased anisotropic percolation clusters (APC). Topologically biased APCs are generated using suitable anisotropic percolation models. New walk dimensions are found to characterize the anisotropic behaviour of the unbiased random walk on the biased topology. Critical properties of electro and magneto conductivities are characterized estimating respective dynamical critical exponents. A dynamical scaling theory relating dynamical and static critical exponents has been developed. The dynamical critical exponents satisfy the scaling relations within error bar.     

Influence of breakup on elastic and α-production channels in the ~6Li+~(116)Sn reaction

The effects of breakup reactions on elastic and α-production channels for the ~6Li+~(116)Sn system have been investigated at energies below and near the Coulomb barrier. The angular distributions of α-particle production differential cross sections have been obtained at several projectile energies between 22 and 40 MeV. The measured breakup α-particle differential cross sections and elastic scattering angular distributions have been compared with the predictions of continuum-discretized coupled channels(CDCC) calculations. The influence of breakup coupling has also been investigated by extracting dynamic polarization potentials(DPP) from the CDCC calculations. From the predictions of CDCC calculations the relative importance of the nuclear, Coulomb, and total breakup contributions have also been investigated. The nuclear breakup couplings are observed to play an important role in comparison to the Coulomb breakup for the direct breakup mechanisms associated in the reaction of ~6Li projectile with ~(116)Sn target nuclei. The influence of strong nuclear breakup coupling exhibits suppression in the Coulomb-nuclear interference peak. The direct breakup cross sections from the CDCC calculations under-predict the measured α-particle differential cross sections at all energies. This suggests that the measured α particles may also have contributions from other possible breakup reaction channels.     

TAT conjugated, FITC doped silica nanoparticles for bioimaging applications

Water-in-oil (w/o) microemulsion synthesis of 70 nm size monodisperse TAT (a cell penetrating peptide, CPP) conjugated, FITC (fluorescein isothiocyanate) doped silica nanoparticles (TAT-FSNPs) is reported; human lung adenocarcinoma (A549) cells (in vitro) and rat brain tissue (in vivo) were successfully labeled using TAT-FSNPs.     

Finite size scaling in BTW like sandpile models

Lattice statistical models of equilibrium critical phenomena generally obey finite size scaling (FSS) ansatz. However, the critical behavior of the prototypical BTW sandpile model demonstrating self-organized criticality at out of equilibrium is described by a peculiar multiscaling behaviour. FSS hypothesis is verified here on two versions (RSM1 and RSM2) of a rotational sandpile model (RSM) with broken mirror symmetry. In these models, sand grains flow only in the forward direction and in a specific rotational direction from an active site after toppling. The toppling rules are such that RSM1 will have less randomness whereas RSM2 will have more randomness with respect to RSM. RSM1 is expected to be more closer to BTW whereas RSM2 is expected to be more closer to Manna’s stochastic model. Both RSM1 and RSM2 are found to belong to the same universality class of RSM. The scaling functions of RSM1 and RSM2 are also found to obey usual FSS hypothesis at out of equilibrium instead of multiscaling as in BTW.