A theoretical prediction of rotating waves in Type-I hydraulic jumps

The rotation of polygons in a Type-II hydraulic jump prompts us to look for a rotational feature in the Type-I hydraulic jump. Coupling the radial and azimuthal flows breaks the azimuthal symmetry of the shallow-water circular jump. An unstable rotating wave along the circumference of the jump is possible with a kinematic viscosity of very small order, whose upper threshold value is less than the kinematic viscosity of water.     

Gravitational plane waves in Einstein-aether theory

In this paper, we systematically study spacetimes of gravitational plane waves in Einstein-aether theory. Due to the presence of the timelike aether vector field, now the problem in general becomes overdetermined. In particular, for the linearly polarized plane waves, there are five independent vacuum Einstein-aether field equations for three unknown functions. Therefore, solutions exist only for particular choices of the four free parameters \(c_{i}\)’s of the theory. We find that there exist eight cases, in two of which any form of gravitational plane waves can exist, similar to that in general relativity, while in the other six cases, gravitational plane waves exist only in particular forms. Beyond these eight cases, solutions either do not exist or are trivial (simply representing a Minkowski spacetime with a constant or dynamical aether field).     

Ultrasmall Ge islands with low diameter-to-height aspect ratio on Si(1 0 0)-(2 × 1) surfaces

Scanning tunneling microscopy (STM) and high resolution cross-sectional transmission electron microscopy (XTEM) studies have been used to investigate the formation of Ge nanocrystals grown on Si(1 0 0)-(2 × 1) surfaces by molecular beam epitaxy (MBE). We observe relatively high density of Ge islands where small ‘pyramids’, small ‘domes’ and facetted ‘domes’ of various sizes co-exist in the film. As revealed from XTEM images, a large fraction of islands, especially dome-shaped Ge islands have been found to have an aspect ratio of ∼1 (diameter):1 (height). Observation of truncated-sphere-shaped Ge islands with a narrow neck contact with the wetting layer is reported.     

Vibrational spectra of nickel metalloporphyrins: An algebraic approach

One of the most interesting areas of current research in molecular physics is the study of the vibrationally excitated states of medium and large molecules. In view of the considerable amount of experimental activity in this area, one needs theoretical models within which to interpret experimental data. Using Lie algebraic method, the vibrational energy levels of nickel metalloporphyrins like Ni(OEP), Ni porphyrin and Ni(TPP) are calculated for 16 vibrational modes. The algebraic Hamiltonian

Adsorption of Cationic Laser Dye onto Polymer/Surfactant Complex Film

Fabrication of complex molecular films of organic materials is one of the most important issues in modern nanoscience and nanotechnology. Soft materials with flexible properties have been given much attention and can be obtained through bottom up processing from functional molecules, where self-assembly based on supramolecular chemistry and designed assembly have become crucial processes and technologies. In this work, we report the successful incorporation of cationic laser dye rhodamine 6G abbreviated as R6G into the pre-assembled polyelectrolyte/surfactant complex film onto quartz substrate by electrostatic adsorption technique. Poly(allylamine hydrochloride) (PAH) was used as polycation and sodium dodecyl sulphate (SDS) was used as anionic surfactant. UV-Vis absorption spec-troscopic characterization reveals the formation of only H-type aggregates of R6G in their aqueous solution and both H- and J-type aggregates in PAH/SDS/R6G complex layer-by-layber films as well as the adsorption kinetics of R6G onto the complex films. The ratio of the absorbance intensity of two aggregated bands in PAH/SDS/R6G complex films is merely independent of the concentration range of the SDS solution used to fabricate PAH/SDS com-plex self-assembled films. Atomic force microscopy reveals the formation of R6G aggregates in PAH/SDS/R6G complex films.     

Design,Synthesis, and Biological Evaluation of 2‐(4‐Aminophenyl)benzothiazole Analogues as Antiproliferative Agents

A series of 28 novel 2‐(4‐aminophenyl)benzothiazole analogues have been synthesized and characterized using various analytical techniques like ¹H NMR, ¹³C NMR, electrospray ionization mass spectrometry, and IR and bioevaluated for their antiproliferative activity over a group of three human cancer cell lines, namely, lung cancer (A549), cervical cancer (HeLa), and breast cancer (MDA‐MB‐231), using sulforhodamine B assay method. Few synthesized molecules ( 5a , 5c , 5d , 5f , 7b , and 7j ) displayed effective growth inhibition (GI₅₀) activity against the tested human cancer cell lines at lower micromolar concentration (GI₅₀) values in the range 0.2–1.7 μM. Noticeably, compound 7b exhibited reasonable activity in all three cancer cell lines in the GI₅₀ range 0.55–1.2 μM. Further, when 7b was screened for tubulin polymerization inhibition, it exhibited more than 55% inhibition at concentration of 5.0 μM. The molecular docking simulations supported the molecular interactions of the derivatives with the targeted receptor. These derivatives may serve as lead structures for development of potential anticancer drug candidates, and 7b might act as a potential microtubule polymerization inhibitor.     

Influence of edge propagation on downward flame spread over three-dimensional PMMA samples

This systematic experimental study measures the effect of flame propagation along vertical edges on the overall downward spread of flames using Polymethyl Methacrylate (PMMA). Samples with a wide range of regular cross-sections – from triangular through octagonal – as well as irregular ones, have been used to test a large variation of internal angles. A MATLAB-based tool was used to calculate instantaneous spread rate for central and edge flames. The edge flame is shown to significantly enhance the spread rate, as much as five times, in respect to samples with no edges. This amplification is shown to depend primarily on the internal angle at the edge (the smaller the angle, the faster the flame) and fuel thickness, and not on other factors such as aspect ratio or cross-sectional area. Using a phenomenological argument, the edge propagation rate is correlated to the spread rate over an equivalent cylindrical fuel (the limiting shape with infinite edges) with an effective radius obtained from the geometry of the edges and the diffusion length scale of the solid phase. A formula for flame spread over cylindrical fuel from the literature is used to link the new results to existing models. Both thick and thin limits are shown to encompass the wide range of three-dimensional spread rate data within the effective radius (the independent variable), which can be determined from the known parameters. Based on these results, different types of cross-sectional areas can be sorted in the order of their inherent fire safety characteristics.     

Development and physicochemical characterization of doxorubicin-encapsulated hydroxyapatite–polyvinyl alcohol nanocomposite for repair of osteosarcoma-affected bone tissues

Nowadays locoregional therapy for cancer treatment can be associated with nanocomposite drug delivery systems. Coated nanoparticles have versatile applications for delivering chemotherapeutic drugs to the targeted part of the body. In this study, a ceramic carrier like nanosized hydroxyapatite (HAp) was synthesized by the in situ precipitation method followed by coating with anticancer drug like doxorubicin (DOX) and polyvinyl alcohol (PVA) polymer. The physicochemical characterization of the prepared polymer-coated drug ceramic nanocomposite (DOX-HAp-PVA) was carried out using Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron spectroscopy, and particle size distribution. Furthermore, the biocompatibility and the anticancer activity of the nanocomposite were explored by MTT assay study. Successfully synthesized DOX-HAp-PVA nanocomposite exhibited a remarkable cytotoxicity toward osteosarcoma cells (MG 63), which may be potentially used as an anticancer agent against osteosarcoma.     

Novel cage clusters of MoS2 in the gas phase

Laser evaporation of MoS(2) nanoflakes gives negatively charged magic number clusters of compositions Mo(13)S(25) and Mo(13)S(28), which are shown to have closed-cage structures. The clusters are stable and do not show fragmentation in the post-source decay analysis even at the highest laser powers. Computations suggest that Mo(13)S(25) has a central cavity with a diameter of 4.5 A. The nanosheets of MoS(2) could curl upon laser irradiation, explaining the cluster formation.     

Search for leptoquark pairs decaying into nunu+jets in pp collisions at square root[s] = 1.8 TeV

We present the results of a search for leptoquark (LQ) pairs in (85.2+/-3.7) pb(-1) of pp* collider data collected by the D0 experiment at the Fermilab Tevatron. We observe no evidence for leptoquark production and set a limit on sigma(pp*-->LQLQ-->nunu+jets) as a function of the mass of the leptoquark (m(LQ)). Assuming the decay LQ-->nuq, we exclude scalar leptoquarks for m(LQ) < 98 GeV/c(2), and vector leptoquarks for m(LQ) < 200 GeV/c(2) and coupling which produces the minimum cross section, at a 95% confidence level.