Dynamical recursive algorithms for Lg-spline interpolation of EHB data

Lg-splines find application in many areas of mathematics, physics, and engineering. Especially in the last, there is need for recursive algorithms suitable for real-time application. In this paper we investigate a dynamical structure of the Hilbert space underlying the spline interpolation problem. We use these insights to develop a recursive algorithm for computing Lg-splines interpolating extended Hermite- Birkhoff data. We also investigate the relationship of our algorithm to a basic theorem due to Jerome and Schumaker regarding the smoothness properties of such splines and to algorithms based on their theorem.     

Improved optical coupling in waveguide photodetectors incorporating a wedge-shaped input facet

A simple method for improving the input coupling in uncleaved waveguide photodetectors is demonstrated. A wedge-shaped recess is incorporated into the input facet to reduce reflection. Over a range of device sizes and wedge shapes, mean quantum efficiency was increased by 16% relative to flat, uncleaved input facets.     

Water and tris(5-acetyl-3-thienyl)methane (TATM) assemble into a one-dimensional channel compound

Tris(5-acetyl-3-thienyl)methane (TATM), a well known hydrophobic host compound, assembles with water molecules into a material with one-dimensional channels that also contain water.     

An embedded 3(2) pair of nonlinear methods for solving first order initial-value ordinary differential systems

In this paper, we present two families of second-order and third-order explicit methods for numerical integration of initial-value problems of ordinary differential equations. Firstly, a family of second-order methods with two free parameters is derived by considering a suitable rational approximation to the theoretical solution of the problem at some grid points. Imposing that the principal term of the local truncation error of this family vanishes, we obtain an expression for one of the parameters in terms of the other. With this approach, a new one-parameter family of third-order methods is obtained. By selecting any 3(2) pair of second and third order methods, they can be implemented as an embedded type method, thus leading to a variable step-size formulation. We have considered one 3(2) pair of second and third order methods and made a comparison of numerical results with several ode solvers which are currently used in practice. The comparison of numerical results shows that the embedded 3(2) pair outperforms the methods considered for comparison.     

New efficient derivative free family of seventh-order methods for solving systems of nonlinear equations

We present a three-step two-parameter family of derivative free methods with seventh-order of convergence for solving systems of nonlinear equations numerically. The proposed methods require evaluation of two central divided differences and inversion of only one matrix per iteration. As a result, the proposed family is more efficient as compared with the existing methods of same order. Numerical examples show that the proposed methods produce approximations of greater accuracy and remarkably reduce the computational time for solving systems of nonlinear equations.     

Concise and Practical Asymmetric Synthesis of a Challenging Atropisomeric HIV Integrase Inhibitor

A practical and efficient synthesis of a complex chiral atropisomeric HIV integrase inhibitor has been accomplished. The combination of a copper‐catalyzed acylation along with the implementation of the BI‐DIME ligands for a ligand‐controlled Suzuki cross‐coupling and an unprecedented bis(trifluoromethane)sulfonamide‐catalyzed tert‐butylation renders the synthesis of this complex molecule robust, safe, and economical. Furthermore, the overall synthesis was conducted in an asymmetric and diastereoselective fashion with respect to the imbedded atropisomer.     

Supramolecular complex induced by the binding of sodium dodecyl sulfate to PAMAM dendrimers

Isothermal titration calorimetry (ITC) and dynamic light scattering (DLS) were employed to study the spontaneous supramolecular complexation of amine terminated PAMAM dendrimer (G3[EDA] PAMAM-NH2) induced by the binding of an anionic surfactant, sodium dodecyl sulfate (SDS). At pHor=10, the electrostatic binding ceased because the deprotonated PAMAM dendrimer was uncharged, and hence the surfactant-induced supramolecular assembly could not be formed.     

3D nanogap interdigitated electrode array biosensors

Three-dimensional interdigitated electrodes (IDEs) have been investigated as sensing elements for biosensors. Electric field and current density were simulated in the vicinity of these electrodes as a function of the electrode width, gap, and height to determine the optimum geometry. Both the height and the gap between the electrodes were found to have significant effect on the magnitude and distribution of the electric field and current density near the electrode surface, while the width of the electrodes was found to have a smaller effect on field strength and current density. IDEs were fabricated based on these simulations and their performance tested by detecting C-reactive protein (CRP), a stress-related protein and an important biomarker for inflammation, cardiovascular disease risk indicator, and postsurgical recuperation. CRP-specific antibodies were immobilized on the electrode surface and the formation of an immunocomplex (IC) with CRP was monitored. Electrochemical impedance spectroscopy (EIS) was employed as the detection technique. EIS data at various concentrations (1 pg/mL to 10 μg/mL) of CRP spiked in buffer or diluted human serum was collected and fitted into an equivalent electrical circuit model. Change in resistance was found to be the parameter most sensitive to change in CRP concentration. The sensor response was linear from 0.1 ng/mL to 1 μg/mL in both buffer and 5% human serum samples. The CRP samples were validated using a commercially available ELISA for CRP detection. Hence, the viability of IDEs and EIS for the detection of serum biomarkers was established without using labeled or probe molecules.     

The Antimicrobial efficacy of Elaeis guineensis: characterization, in vitro and in vivo studies

The urgent need to treat multi-drug resistant pathogenic microorganisms in chronically infected patients has given rise to the development of new antimicrobials from natural resources. We have tested Elaeis guineensis Jacq (Arecaceae) methanol extract against a variety of bacterial, fungal and yeast strains associated with infections. Our studies have demonstrated that E. guineensis exhibits excellent antimicrobial activity in vitro and in vivo against the bacterial and fungal strains tested. A marked inhibitory effect of the E. guineensis extracts was observed against C. albicans whereby E. guineensis extract at ?, 1, or 2 times the MIC significantly inhibited C. albicans growth with a noticeable drop in optical density (OD) of the bacterial culture. This finding confirmed the anticandidal activity of the extract on C. albicans. Imaging using scanning (SEM) and transmission (TEM) electron microscopy was done to determine the major alterations in the microstructure of the extract-treated C. albicans. The main abnormalities noted via SEM and TEM studies were the alteration in morphology of the yeast cells. In vivo antimicrobial activity was studies in mice that had been inoculated with C. albicans and exhibited good anticandidal activity. The authors conclude that the extract may be used as a candidate for the development of anticandidal agent.     

Optimized mean based second derivative-free families of Chebyshev–Halley type methods

In this paper, we present new interesting fourth-order optimal families of Chebyshev–Halley type methods free from second-order derivative. In terms of computational cost, eachmember of the families requires two functions and one first-order derivative evaluation per iteration, so that their efficiency indices are 1.587. It is found by way of illustration that the proposed methods are useful in high-precision computing environment. Moreover, it is also observed that larger basins of attraction belong to ourmethods although the othersmethods are slow and have darker basins while some of the methods are too sensitive upon the choice of the initial guess.