Dual Feynman rules—Topological asymptotic freedom

Feynman-graph rules are formulated for the strong—interaction components of the topological expansion—defined as those graphs all of whose vertices are zero—entropy connected parts. These rules imply a “topological asymptotic freedom” and admit a corresponding perturbative evaluation where the zeroth order exhibits topological supersymmetry.     

Resonance structure in 15N(p,n0)15O in the region Ep = 8.5–19.0 MeV

Excitation functions at seven angles, covering the energy range E_p = 8.5–19.0 MeV, have been measured for ¹⁵N(p, n_o)¹⁵O using time-of-flight methods. Angular distributions were also measured at five energies. Activation methods were used to determine the total cross section below the excited-state threshold. Ten resonances were observed, four of which have also been found in ¹⁵N(p, γ)¹⁶O data. The energies, widths and nucleon widths have been extracted and are used, together with proton capture data, to derive radiative widths for certain levels.     

Application of fluid dynamic gauging to annular test apparatuses for studying fouling and cleaning

Fluid dynamic gauging (FDG) is a non-contact technique for measuring the thickness and strength of fouling layers immersed in liquid in situ. Its application to an annular geometry across a range of possible flow conditions, from stagnant to turbulent flow regimes (annulus Reynolds number ∼29,000), is demonstrated. Two modes of measurement are demonstrated: in the first, the pressure drop across the nozzle is fixed and the mass flow rate of liquid withdrawn through the gauge is measured. In the second, the mass flow rate of liquid is fixed and the pressure drop measured: the latter is a new mode of measurement and it is shown to perform equally well, with advantages for particular applications. The results were not affected significantly by the surface under study being heated, indicating that the technique is suitable for measuring deposit thicknesses insitu during fouling and cleaning experiments in annular devices which are commonly used in deposition studies. Computational fluid dynamics (CFD) simulations, which afford detailed information about the flow patterns and shear stresses imposed on the surface, showed good agreement with experimental data for tests in the laminar regime: simulation of the transitional and turbulent regimes was not attempted. A short study of whey protein fouling recorded mixed success owing to the softness of the deposit, but demonstrated the scope for FDG to monitor the development of fouling layers in these geometries.     

Biotinylated fluorescent probe for the specific and quantitative determination of blood glucose

The quantitative detection of biomarkers in protein‐rich samples using fluorescent probes is usually hampered by nonspecific fluorescence as a result of nonspecific probe–protein interactions. In this paper, we report a biotinylated fluorescent probe that is encapsulated in avidin protein, which can generate very specific fluorescence in blood serum by blocking out nonspecific dye–protein interactions. This approach was applied successfully to quantify glucose concentrations in blood serum.     

Enantiomeric pairs of copper(II) polypyridyl-alanine complex salts: anticancer studies

The anticancer properties of two previously characterized pairs of optically pure chiral complex salts [Cu(phen)(ala)(H₂O)]X·xH₂O (phen?=?1.10-phenanthroline; X?=?NO₃^?; ala: l-alanine (l-ala) 1 and d-alanine (d-ala) 2; and (X?=?Cl^?; ala: l-ala, 3 and d-ala, 4; x?=?number of lattice water molecules) are reported herein, together with the crystal structure of the d-enantiomer 4. Unlike cisplatin which is ineffective against MCF-7 cancer cells with the absence of caspase-3 protein expression, these two pairs of complex salts were effective against this cell line and they were able to induce an increase in intracellular ROS, loss in mitochondrial membrane potential, cell cycle arrest mainly at SubG1 phase , caspase-9 activation, and caspase-3/caspase-7-independent apoptosis. Screening of 1 on the NCI-60 panel of human cancer cell lines showed that it was effective against most of the cell lines. MTT-NCI modified assay screening was also done on other cancer cell lines, viz. A549, CNE1, and HepG2, and two normal cell lines, viz. MCF-10A and CHANG. The effects of chirality of these Cu(II) compounds, especially the greater selectivity of d-enantiomers over the l-counterparts, on their anticancer properties are also reported herein.     

Dynamic light scattering from micelle complexes of cetyltrimethylammonium bromide-sodium salicylate in aqueous solutions

The diffusion coefficient of cetyltrimethylammonium bromide-sodium salicylate in aqueous solutions has been determined, using the dynamic light-scattering technique, as a function of sodium salicylate concentration, as well as of temperature. Using a gel model the results are discussed in terms of intermicellar pseudo-linkages, entanglements of threadlike micelles, and formation of pseudo-network.     

An improved method for the preparations of nanostructured lipid carriers containing heat-sensitive bioactives

Heat-sensitive bioactive compounds such as β-carotene and tocols, are widely used in the pharmaceutical and cosmetic fields. Their chemical stability in delivery systems is one of the major concerns in the production of nanostructured lipid carriers (NLCs). A previously established high-temperature high-pressure homogenisation technique involved in the preparation of NLCs can cause degradation of heat-sensitive compounds. Therefore, a novel preparation process needs to be developed to minimise the degradation of heat-sensitive active compounds during the preparation of NLCs. In this work, modified methods A and B were designed to minimise the degradation of β-carotene and tocols during the production of NLCs. These methods improved the chemical stability of heat-sensitive bioactive compounds (β-carotene and tocols) significantly compared to the previously established method. The physical stability of the formulation was maintained throughout study duration.     

An Optimization Based Approach to the Train Operator Scheduling Problem at Singapore MRT

Singapore Mass Rapid Transit (SMRT) operates two train lines with 83 kilometers of track and 48 stations. A total of 77 trains are in operation during peak hours and 41 during off-peak hours. In this article we report on an optimization based approach to develop a computerized train-operator scheduling system that has been implemented at SMRT. The approach involves a bipartite matching algorithm for the generation of night duties and a tabu search algorithm for the generation of day duties. The system automates the train-operator scheduling process at SMRT and produces favorable schedules in comparison with the manual process. It is also able to handle the multiple objectives inherent in the crew scheduling system. While trying to minimize the system wide crew-related costs, the system is also able to address concern with respect to the number of split duties.     

A Monte Carlo approach for estimating measurement uncertainty using standard spreadsheet software

Despite the importance of stating the measurement uncertainty in chemical analysis, concepts are still not widely applied by the broader scientific community. The Guide to the expression of uncertainty in measurement approves the use of both the partial derivative approach and the Monte Carlo approach. There are two limitations to the partial derivative approach. Firstly, it involves the computation of first-order derivatives of each component of the output quantity. This requires some mathematical skills and can be tedious if the mathematical model is complex. Secondly, it is not able to predict the probability distribution of the output quantity accurately if the input quantities are not normally distributed. Knowledge of the probability distribution is essential to determine the coverage interval. The Monte Carlo approach performs random sampling from probability distributions of the input quantities; hence, there is no need to compute first-order derivatives. In addition, it gives the probability density function of the output quantity as the end result, from which the coverage interval can be determined. Here we demonstrate how the Monte Carlo approach can be easily implemented to estimate measurement uncertainty using a standard spreadsheet software program such as Microsoft Excel. It is our aim to provide the analytical community with a tool to estimate measurement uncertainty using software that is already widely available and that is so simple to apply that it can even be used by students with basic computer skills and minimal mathematical knowledge.     

Modeling fluid-particle interaction in dilute-phase turbulent liquid-particle flow simulation

The present work examines the predictive capability of a two-fluid CFD model that is based on the kinetic theory of granular flow in simulating dilute-phase turbulent liquid-particle pipe flows in which the inter-stitial fluid effect on the particle fluctuating motion is significant.The impacts of employing different drag correlations and turbulence closure models to describe the fluid-particle interactions(i.e.drag force and long-range interaction)are examined at both the mean and fluctuating velocity levels.The model pre-dictions are validated using experimental data of turbulent liquid-particle flows in a vertical pipe at different particle Reynolds numbers(ReP > 400 and ReP < 400),which characterize the importance of the vortex shedding phenomenon in the fluid-phase turbulence modulation.The results indicate that(1)the fluctuating velocity level predictions at different ReP are highly sensitive to the drag correlation selec-tion and(2)different turbulence closure models must be employed to accurately describe the long-range fluid-particle interaction in each phase.In general,good agreement is found between the model predic-tions and the experimental data at both the mean and fluctuating velocity levels provided that appropriate combinations of the drag correlation and the turbulence closure model are selected depending on Rep.