Reaction of Tröger’s base analogues with Vilsmeier reagents

As part of a program aimed at introducing functionality onto the Tröger’s base framework post-synthesis, we investigated the formylation reaction of Tröger’s base analogues with Vilsmeier reagents. We found that rather than the anticipated reaction at the aryl rings, these compounds react with Vilsmeier reagents to afford compounds with a modified strap, whereby the apical methylene group is replaced by a methylene strap bearing an N,N-disubstituted amine.     

He-Ne laser-induced improvement in biochemical, physiological, growth and yield characteristics in sunflower (Helianthus annuus L.)

The water-soaked seeds of sunflower were exposed to low power continuous wave He-Ne laser irradiation of energies 0, 100, 300 and 500 mJ to evaluate the effect on various biochemical, physiological, growth and yield parameters of sunflower. The experiments which consisted of four replicates arranged in a completely randomized design (CRD) were carried out under the greenhouse conditions. The physiological attributes like, photosynthetic rate (A), transpiration rate (E), intrinsic CO(2) concentration (C(i) ), stomatal conductance (g(s)), chlorophyll a and b contents, relative membrane permeability and leaf water (ψ(w)), osmotic (ψ(s)) and turgor (ψ(p)) potentials, relative water contents and leaf area increased significantly as compared to control due to He-Ne treatment of seeds. The activities of superoxide dismutase, peroxidase and catalases and contents of total soluble proteins, malondialdehyde, proline and leaf total phenolic also increased due to laser treatment. Significant increase in growth parameters of sunflower like shoot fresh and dry masses, root fresh and dry masses, root and shoot lengths, number of leaves per plant and stem diameter has also been observed. The contents of K, Ca and Mg in shoot and root were also increased and an overall increase of up to 28.12% was observed due to laser treatment.     

Alkali hydrolysis of trinitrotoluene

Data for alkali hydrolysis of 2,4,6-trinitrotoluene (TNT) in aqueous solution at pH 12.0 under static (pH-controlled) as well as dynamic (pH-uncontrolled) conditions are reported. The experiments were conducted at two different molar ratios of TNT to hydroxyl ions at room temperature. The TNT disappeared rapidly from the solution as a first-order reaction. The complete disappearance of aromatic structure from the aqueous solution within 24 h was confirmed by the ultraviolet-visible (UV-VIS) spectra of the samples. Cuvet experiments in a UV-VIS spectrophotometer demonstrated the formation of Meisenheimer complex, which slowly disappeared via formation of aromatic compounds with fewer nitro groups. The known metabolites of TNT were found to accumulate only in very small quantities in the liquid phase.     

The Application of Fractal Transform and Entropy for Improving Fault Tolerance and Load Balancing in Grid Computing Environments

This paper applies the entropy-based fractal indexing scheme that enables the grid environment for fast indexing and querying. It addresses the issue of fault tolerance and load balancing-based fractal management to make computational grids more effective and reliable. A fractal dimension of a cloud of points gives an estimate of the intrinsic dimensionality of the data in that space. The main drawback of this technique is the long computing time. The main contribution of the suggested work is to investigate the effect of fractal transform by adding R-tree index structure-based entropy to existing grid computing models to obtain a balanced infrastructure with minimal fault. In this regard, the presented work is going to extend the commonly scheduling algorithms that are built based on the physical grid structure to a reduced logical network. The objective of this logical network is to reduce the searching in the grid paths according to arrival time rate and path’s bandwidth with respect to load balance and fault tolerance, respectively. Furthermore, an optimization searching technique is utilized to enhance the grid performance by investigating the optimum number of nodes extracted from the logical grid. The experimental results indicated that the proposed model has better execution time, throughput, makespan, latency, load balancing, and success rate.     

Impact of Linear Operator on the Convergence of HAM Solution: A Modified Operator Approach

The linear operator plays an important role in the computational process of Homotopy Analysis Method (HAM). In HAM frame any kind of linear operator can be chosen to develop a solution. Hence, it is easy to introduce the modified/physical parameter dependent linear operators. The effective use of these operators has been judged through solving fluid flow problems. Modification in linear operators affects the solution and improves the computational efficiency of HAM for larger values of parameters. The convergence rate of the solution is rapid and several times higher resulting in less computational time.     

Caulerpin

The crystal structure of caulerpin (di­methyl 6,13‐di­hydro­dibenzo­[b,i]­phenazine‐5,12‐di­carboxyl­ate, C₂₄H₁₈N₂O₄), an indole alkaloid, reported in space group Cc with an acute β angle, has been redetermined in the correct space group, C2/c. The mol­ecule has twofold crystallographic symmetry and is composed of two essentially planar indole groups fused to an eight‐membered cyclo­octatetraene ring which adopts a boat conformation. The molecular dimensions are normal. The structure is stabilized by intermolecular and intramolecular interactions involving the indole N—H atom and carbonyl O atom [N?O 3.211 (4) and 2.836 (4) Å].     

Chemical Markers and Pharmacological Characters of Pelargonium graveolens Essential Oil from Palestine

Pelargonium graveolens leaves are widely used in traditional medicine for relieving some cardiovascular, dental, gastrointestinal, and respiratory disorders. They are also used as food and tea additives in Palestine and many other countries. Consequently, this investigation aimed to describe the chemical markers, cytotoxic, antioxidant, antimicrobial, metabolic, and cyclooxygenase (COX) enzymes inhibitory characteristics of P. graveolens essential oil (PGEO) from Palestine utilizing reference methods. There were 70 chemicals found in the GCMS analysis, and oxygenated terpenoids were the most abundant group of the total PGEO. Citronellol (24.44%), citronellyl formate (15.63%), γ-eudesmol (7.60%), and iso-menthone (7.66%) were the dominant chemical markers. The EO displayed strong antioxidant activity (IC₅₀ = 3.88 ± 0.45 µg/mL) and weak lipase and α-amylase suppressant effects. Notably, the PGEO displayed high α-glucosidase inhibitory efficacy compared with Acarbose, with IC₅₀ doses of 52.44 ± 0.29 and 37.15 ± 0.33 µg/mL, respectively. PGEO remarkably repressed the growth of methicillin-resistant Staphylococcus aureus (MRSA), even more than Ampicillin and Ciprofloxacin, and strongly inhibited Candida albicans compared with Fluconazole. The highest cytotoxic effect of the PGEO was noticed against MCF-7, followed by Hep3B and HeLa cancer cells, with IC₅₀ doses of 32.71 ± 1.25, 40.71 ± 1.89, and 315.19 ± 20.5 µg/mL, respectively, compared with doxorubicin. Moreover, the screened EO demonstrated selective inhibitory activity against COX-1 (IC₅₀ = 14.03 µg/mL). Additionally, PGEO showed a weak suppressant effect on COX-2 (IC₅₀ = 275.97 µg/mL). The current research can be considered the most comprehensive investigation of the chemical and pharmacological characterization of the PGEO. The results obtained in this study demonstrate, without doubt, that this plant represents a rich source of bioactive substances that can be further investigated and authenticated for their medicinal potential.     

Composite liquid crystal-polymer electrolytes in dye-sensitised solar cells: effects of mesophase alkyl chain length

The doping of polymer electrolytes (PEs) with liquid crystal (LC) materials has been shown to improve the performance of dye-sensitised solar cells (DSSCs). This is achieved by promoting ionic conduction and increasing optical path length through multiple-light scattering within the photovoltaic devices. In LCs, it is well known that the length of the alkyl chain plays an important role since the LC morphology and mesophase stabilisation depend strongly on the alkyl group. In this work, liquid crystal-polymer composite electrolytes (LC-PEs) are prepared using nematic LCs with different alkyl chain lengths. The morphology of the LC-PEs is investigated and correlated with their electrical properties. Subsequently, DSSCs are prepared using the LC-PEs as a direct example of its application. It is shown that increasing the alkyl chain length of the LCs reduces the efficiency of the solar devices. The longer alkyl chains are speculated to intertwine, thus trapping the mobile ions and reducing the bulk ionic conductivity. For the same reason, longer alkyl chain LCs are thought to be unable to passivate the TiO₂ surface through the adsorption of cyanobiphenyl groups and hence the higher probability of back recombination reaction between the electrons in TiO₂ and PE.     

Semiempirical Predictions of Chemical Degradation Reaction Mechanisms of CL-20 as Related to Molecular Structure

Combining computer chemistry calculation with experimental verification is useful both in proving concepts and what is chemically possible. Computational predictions, using MOPAC quantum mechanical and classical force field mechanics, were used to investigate most likely first-tier intermediates of cyclic and cage cyclic nitramines—comparing bond lengths and angles, heats of formation, steric energy, dipole moments, solvent accessibility and electrostatic potential surfaces, partial charges, and Highest Occupied Molecular Orbitals/Lowest Unoccupied Molecular Orbitals (HOMO/LUMO) energies. Two competing modes of degradation are summarized: through addition of hydroxide ions and through addition of photo-induced free radicals. UV/VIS measured concentrations and followed the course of reactions. FTIR followed CL-20 degradation through alkali hydrolysis, where FTIR measurements verified theoretical predictions.     

Three‐dimensional flow of an elastico‐viscous fluid with mass transfer

This paper looks at the unsteady three‐dimensional MHD flow of an elastico‐viscous fluid over a stretching surface. The analysis of mass transfer is also analyzed. The governing boundary layer equations are reduced into partial differential equations with three dependent variables through similarity transformations. The transformed system of equations is solved analytically by employing homotopy analysis method (HAM). Plots for various interesting parameters are presented and discussed. Numerical data for surface shear stresses and surface mass transfer in steady case are also tabulated. Copyright © 2010 John Wiley & Sons, Ltd.