Stimuli‐Responsive Cycloaurated “OFF‐ON” Switchable Anion Transporters

Anion transporters have shown potential application as anti‐cancer agents that function by disrupting homeostasis and triggering cell death. In this research article we report switchable anion transport by gold complexes of anion transporters that are “switched on” in situ in the presence of the reducing agent GSH by decomplexation of gold. GSH is found in higher concentrations in tumors than in healthy tissue and hence this approach offers a strategy to target these systems to tumors.     

A general one-equation turbulence model for free shear and wall-bounded flows

The purpose of thiswork is to introduce a complete and general one-equation model capable of correctly predicting a wide class of fundamental turbulent flows like boundary layer, wake, jet, and vortical flows. The starting point is the mature and validated two-equation k−ω turbulence model of Wilcox. The newly derived one-equation model has several advantages and yields better predictions than the Spalart-Allmaras model for jet and vortical flows while retaining the same efficiency and quality of the results for near-wall turbulent flows without using a wall distance. The derivation and validation of the new model using findings computed by the Spalart-Allmaras and the k−ω models are presented and discussed for several free shear and wall-bounded flows.     

All-fiber acousto-optic polarization monitor

We describe the operational principle of and experimentally demonstrate a narrowband, wavelength-tunable polarization monitor based on a fiber acousto-optic tunable filter. Two orthogonally vibrating acoustic waves are used to create a variable polarizer that can be used to measure the state of polarization of an incident narrowband light source. The accuracy of the polarization monitor is measured at two different wavelengths in reference to a commercial polarimeter and is shown to be within 5%.     

Hydrogen Bonded, π···π Stacked and X···π Framework Structures in Bis(2,6-Lutidinium) Tetrahalocuprate(II) Complexes

Abstract  

In the crystal structures of (2,6-lutidinium)₂[CuCl₄], 1 and (2,6-lutidinium)₂[CuBr₄], 2, the anion CuX₄ ²⁻ is connected to eight and four surrounding cations in 1 and 2, respectively, through (N–H···X) (H₂C–H···X) and (C–H···X) hydrogen bonds to form two-dimensional layers approximately normal to the crystallographic b-axis. These layers are further connected by means of offset face-to-face interactions (parallel to b-axis) to give three-dimensional structures. The hydrogen bonding (type and number) around each anion could be influenced by the anion size, as same cation is used, allowing different cation…anion interpenetrations.     

Optimal control of the dynamic response of an anisotropic plate with various boundary conditions

The problem of minimising the dynamic response of an anisotropic rectangular plate with minimum possible expenditure of force is presented for various cases of boundary conditions. The plate has a principal direction of anisotropy rotated at an arbitrary angle relative to the coordinate axes. This orientation angle has been taken as an optimisation design parameter. The control problem is formulated as an optimisation problem by using a performance index, which comprises a weight sum of the control objective and penalty function of the control force. The explicit solutions for the closed-loop distributed control function is obtained by means of Liapunov-Bellman theory. To assess the present solution, numerical results are presented to illustrate the effect of anisotropy ratio, orientation angle, aspect ratio and boundary conditions on the control process.     

Some convergence aspects of the one-center expansion methods

Among the methods that may be used to carry out multicenter integrals over STOS, the one-center two-range expansion is probably the oldest one. However, the convergence of the leading series is generally slow and, hence, time-consuming. Therefore, it was the aim of the present work to show that the so-called nonlinear sequence transformations may be of substantial help for improving the rate of convergence of such series. © 1994 John Wiley & Sons, Inc.     

Coupling semiconductor lasers into single-mode optical fibers by use of tips grown by photopolymerization

We show that a polymer tip, integrated by free-radical photopolymerization at the end of a telecommunication optical fiber, allows high-efficiency coupling between the fiber and an infrared laser diode. A coupling efficiency of 70% (1.5-dB loss) was achieved. We obtained this result by controlling the radius of curvature of the tip, the origin of which is discussed in terms of the photochemical influence of oxygen during tip formation. The experimental data were found to be in agreement with results of electromagnetic calculations based on the finite-element method.     

Photocycloaddition of chalcones to yield cyclobutyl ditopic cyclophanes

The intramolecular photocycloaddition of chalcones to give cyclobutanes has proved to be a fast and convenient method to shrink a cyclophane ring to a tricyclic system, in order to prepare potential ditopic receptors. X-Ray results confirm the previously indicated structure for the cyclobutanes 2a (n=1, m=1), in which the cyclization occurs by a head-to-head syn ring closure. NMR results indicate that the same process occurs for the cyclobutanes 2b (n=2, m=2) and 2c (n=1, m=3).