Growth of manganese tartrate trihydrate in silica gel

Growth of manganese tartrate trihydrate crystals in silica gel media with manganese chloride and manganese sulphate as the reactant is attempted. The reason for the occurrence of platelets along with dendrites in the case of manganese sulphate is discussed. IR, X-ray, atomic absorption and thermogravimetric techniques are employed to characterize the grown crystals and the results are discussed.     

Energy localization and white noise-induced enhancement of response in a micro-scale oscillator array

In this work, the authors seek to develop an analytical framework to understand the influence of noise on an array of micro-scale oscillators with special attention to the phenomenon of intrinsic localized modes (ILMs). It was recently shown by one of the authors and co-workers (Dick et al. in Nonlinear Dyn. 54:13, 2008) that ILMs can be realized as nonlinear vibration modes. Building on this work, it is shown here that white noise excitation, by itself, is unable to produce ILMs in an array of coupled nonlinear oscillators. However, in the case of an array subjected to a combined deterministic and random excitation, the obtained numerical results indicate the existence of a threshold noise strength beyond which the ILM at one location in attenuated whilst the localization in strengthened at another location in the array. The numerical results further motivate the formulation of a general analytical framework wherein the Fokker–Planck equation is derived for a typical coupled oscillator cell of the array subjected to a combined white noise and deterministic excitation. With a set of approximations, the moment evolution equations are derived from the Fokker–Planck equation and they are numerically solved. These solutions indicate that once a localization event occurs in the array, a random excitation with noise strength above a threshold value contributes to the sustenance of the event. It is also observed that an excitation with a higher noise strength results in enhanced response amplitudes for oscillators in the center of the array. The efforts presented in this paper, in addition to providing an analytical framework for developing a fundamental understanding of the influence of white noise on the dynamics of coupled oscillator arrays, suggest that noise may be potentially used to manipulate the formation and persistence of ILMs in such arrays. Furthermore, the occurrence of enhanced response amplitudes due to an excitation with a high noise strength indicates that the framework may also be used to investigate stochastic resonance-type phenomena in coupled arrays of nonlinear oscillators including micro-scale oscillator arrays.     

Raman spectral investigations on the binary system (acetic acid N,N‐dimethyl formamide)

Raman spectra of acetic acid (AA), N,N‐dimethyl formamide (DMF) and their binary mixtures with varying mole fraction of the AA were recorded in the region 300–1750 cm⁻¹ to investigate the formation of self‐associated dimer and hydrogen‐bonded complexes in a mixed system. The observed spectral features of the CO stretching mode suggest the formation of self‐association with a smaller aggregation size, and also indicate the presence of repulsive interactions between AA and DMF. The existence of two kinds of AA molecules (free and complex) is elucidated from the splitting of the OC O deformation mode. The intermolecular hydrogen‐bond formation and the possibility of attractive interaction between AA and DMF are also examined from the observed spectral features in the CCO symmetric stretching mode of AA, and CN symmetric stretching mode of DMF. Copyright © 2006 John Wiley & Sons, Ltd.     

Raman Scattering Studies on the Thin Graded Band Gap AlGaAs Hetero-Epitaxial Layer

Thin graded hetero-epitaxial AlGaAs layer has been grown from the undersaturated Liquid Phase Epitaxial (LPE) technique. The grown layers have been characterized using Laser Raman scattering studies. The peak position and intensity ratio of GaAs and AlAs like LO phonon frequencies have been measured and compared with conventional LPE grown AlGaAs epitaxial layer. The behaviour of GaAs and AlAs like LO phonons has been found to vary with the aluminum composition in the grown layer. Raman peak positions have been observed to shift to lower wavenumber in GaAs like LO phonon and higher wavenumber side of AlAs like LO phonon. Aluminum free features have been noticed in IEE grown AlGaAs (x > 0.8) hetero epitaxial layers.     

Implementing modular adaptation of scientific software

Scientific software often needs to be adapted for different execution environments, problem sets, and available resources to ensure its efficiency and reliability. However, for existing programs, implementing adaptations by directly modifying source code can be time-consuming, error-prone, and difficult to manage for today's complex software. In this paper, we present a modular approach to realizing adaptation for existing scientific codes. By treating adaptation as a separate concern, our approach supports the development of application-specific, context-aware adaptation schemes without directly modifying the original code. Our approach uses a compositional framework that offers language-neutral mechanisms to integrate separately written adaptation code with existing code. Using our approach, scientific programmers can focus on the design and implementation of adaptation schemes separately from the original code development, and then compose an adaptive application whose original capabilities are enhanced in diverse aspects such as performance and stability. Our compositional approach enables fine-grained adaptation, so that an application's program behavior is controlled at the function or algorithm level by adaptation code plugged into the application. By applying our approach to real-world scientific applications to implement various adaptation scenarios, we demonstrate applicability and effectiveness for adapting scientific software.     

Integrated Machine Learning and Chemoinformatics-Based Screening of Mycotic Compounds against Kinesin Spindle ProteinEg5 for Lung Cancer Therapy

Among the various types of cancer, lung cancer is the second most-diagnosed cancer worldwide. The kinesin spindle protein, Eg5, is a vital protein behind bipolar mitotic spindle establishment and maintenance during mitosis. Eg5 has been reported to contribute to cancer cell migration and angiogenesis impairment and has no role in resting, non-dividing cells. Thus, it could be considered as a vital target against several cancers, such as renal cancer, lung cancer, urothelial carcinoma, prostate cancer, squamous cell carcinoma, etc. In recent years, fungal secondary metabolites from the Indian Himalayan Region (IHR) have been identified as an important lead source in the drug development pipeline. Therefore, the present study aims to identify potential mycotic secondary metabolites against the Eg5 protein by applying integrated machine learning, chemoinformatics based in silico-screening methods and molecular dynamic simulation targeting lung cancer. Initially, a library of 1830 mycotic secondary metabolites was screened by a predictive machine-learning model developed based on the random forest algorithm with high sensitivity (1) and an ROC area of 0.99. Further, 319 out of 1830 compounds screened with active potential by the model were evaluated for their drug-likeness properties by applying four filters simultaneously, viz., Lipinski’s rule, CMC-50 like rule, Veber rule, and Ghose filter. A total of 13 compounds passed from all the above filters were considered for molecular docking, functional group analysis, and cell line cytotoxicity prediction. Finally, four hit mycotic secondary metabolites found in fungi from the IHR were screened viz., (−)-Cochlactone-A, Phelligridin C, Sterenin E, and Cyathusal A. All compounds have efficient binding potential with Eg5, containing functional groups like aromatic rings, rings, carboxylic acid esters, and carbonyl and with cell line cytotoxicity against lung cancer cell lines, namely, MCF-7, NCI-H226, NCI-H522, A549, and NCI H187. Further, the molecular dynamics simulation study confirms the docked complex rigidity and stability by exploring root mean square deviations, root mean square fluctuations, and radius of gyration analysis from 100 ns simulation trajectories. The screened compounds could be used further to develop effective drugs against lung and other types of cancer.     

A complete mapping of the positions of the proteins in the small ribosomal subunit of escherichia coli

The relative positions of the centers of mass of the 21 proteins of the 30S ribosomal subunit from Escherichia coli have been determined by triangulation using neutron scattering measurements in solution. This mapping is the first complete account of the quaternary structure of the small ribosomal subunit to be obtained by any method.     

Mutually exclusive hole and electron transfer coupling in cross stacked acenes

The topology of frontier molecular orbitals (FMOs) induces highly sensitive charge transfer coupling with variation in the intermolecular arrangement. A consistent optoelectronic property correlated to a specific aggregate architecture independent of the nature of the monomer is a rare phenomenon. Our theoretical investigation on stacked dimeric systems of linear [n]acenes (n = 2–5) and selected non-linear acenes with a D_2h point group reveals that the Greek cross (+) stacked orientation, irrespective of the molecular candidate, exhibits mutually exclusive hole and electron transfer couplings. The deactivation of either hole or electron transfer coupling is a consequence of the zero inter-orbital overlap between the highest occupied molecular orbitals (HOMOs) or lowest unoccupied molecular orbitals (LUMOs) of the monomers possessing gerade symmetry. In the Greek cross (+) stacked alignment, the (4n + 2) π-electronic acene systems with an odd number of benzenoids exhibit exclusive electron transfer coupling, while the even numbered acenes exhibit selective hole transfer coupling. The trend is reversed for representative 4n π-electronic acene systems. The effect of mutually exclusive charge transfer coupling in the hopping regime of charge transport was evaluated using semiclassical Marcus theory, and selective charge carrier mobility was exhibited by the Greek cross (+) stacks of the considered acene candidates. Additionally, the characteristic charge transfer coupling of the orthogonal acene stacks resulted in negligible short-range exciton coupling, inciting null exciton splitting at short interplanar distances. Engineering chromophores in precise angular orientations ensuring characteristic emergent properties can have tremendous potential in the rational design of advanced optoelectronic materials.

Acenes in the Greek cross (+) stack orientation exhibit selective hole and electron transfer coupling based on gerade symmetry in frontier molecular orbitals.