Emission Control by Molecular Manipulation of Double‐Paddled Binuclear PtII Complexes at the Air‐Water Interface

Molecular functions depend on conformations and motions of the corresponding molecular species. An air–water interface is a suitable asymmetric field for the control of molecular conformations and motions under a small applied force. In this work, double‐paddled binuclear Pt^II complexes containing pyrazole rings linked by alkyl spacers were synthesized and their orientations and emission properties dynamically manipulated at the air–water interface. The complexes emerge from water with concurrent variation of interface orientation of the planes of the Pt^II complexes from perpendicular to parallel during mechanical compression suggesting a unique ‘submarine emission‘. Phosphorescence of the complexes is quenched at the air–water interface prior to monolayer formation with intensities subsequently rapidly increasing during monolayer compression. These results indicate that asymmetric reactions and motions might be controlled by applying mechanical force at the air–water interface.     

Optical Properties of CuInSe2 Thin Films Prepared by R.F. Sputtering

The optical absorption of r.f. sputtered CuInSe₂ thin films was studied in the photon energy range from 1 to 3 eV. The gap energy and the spin-orbit splitting are found to be (1.01 ± 0.01) eV and (0.24 ± 0.02) eV, respectively. From the photon energy dependence of the absorption coefficient it is concluded that the heavy and light hole bands are parabolic whilst the split-off band contains terms linear in the wavevector. The optical transition probability for valence band- to- conduction band transitions is estimated to be (10.8 ± 1.0) eV which yields an admixture of copper d states to the valence band of (30 ± 8) %.     

Antibacterial Activity of Pharmaceutical-Grade Rose Bengal: An Application of a Synthetic Dye in Antibacterial Therapies

Rose bengal has been used in the diagnosis of ophthalmic disorders and liver function, and has been studied for the treatment of solid tumor cancers. To date, the antibacterial activity of rose bengal has been sporadically reported; however, these data have been generated with a commercial grade of rose bengal, which contains major uncontrolled impurities generated by the manufacturing process (80–95% dye content). A high-purity form of rose bengal formulation (HP-RBf, >99.5% dye content) kills a battery of Gram-positive bacteria, including drug-resistant strains at low concentrations (0.01–3.13 μg/mL) under fluorescent, LED, and natural light in a few minutes. Significantly, HP-RBf effectively eradicates Gram-positive bacterial biofilms. The frequency that Gram-positive bacteria spontaneously developed resistance to HP-RB is extremely low (less than 1 × 10⁻¹³). Toxicity data obtained through our research programs indicate that HP-RB is feasible as an anti-infective drug for the treatment of skin and soft tissue infections (SSTIs) involving multidrug-resistant (MDR) microbial invasion of the skin, and for eradicating biofilms. This article summarizes the antibacterial activity of pharmaceutical-grade rose bengal, HP-RB, against Gram-positive bacteria, its cytotoxicity against skin cells under illumination conditions, and mechanistic insights into rose bengal’s bactericidal activity under dark conditions.     

Effect of plasma hydrogenation on the defect properties of CuInSe2 single crystals

The defect properties of p-type CuInSe₂ single crystals hydrogenated by diffusion from a plasma source are investigated using the Rutherford backscattering/channeling technique and photoacoustic spectroscopy. Plasma hydrogenation is found to produce severe lattice damage, to affect the intrinsic defect equilibrium in the near surface region of the crystals and to create an additional donor. A defect formation model including both defect passivation by hydrogen and damage induced defect creation is proposed to explain the experimental data. The thermal stability of the property modifications is limited to temperatures below about 100 °C.     

Correction to: Interlaboratory Reproducibility of Contour Method Data Analysis and Residual Stress Calculation

Experimental Mechanics - The original version of this article has been corrected to include authors middle initials in the author list. The details given in this correction are correct.     

Recent developments in the radiation chemistry of elastomers

The radiation chemistry of several elastomers has been reviewed, including that of polybutadiene, polyisoprene, polyisobutylene, halogenated rubbers, ethylene-alkene copolymers and a range of polyurethanes. The properties investigated include the yields of volatile products and radicals and the new chemical structures formed on radiolysis. The roles of double bonds and hetero-atoms, such as chlorine, in the radiation chemistry of the elastomers has also been discussed.     

A highly efficient synthesis of [1-C, O]- and [1-C, H2]-glycerol for the elucidation of biosynthetic pathways

Labeled glycerol is a widely used biochemical probe to investigate biosynthetic pathways. A highly efficient synthesis of [1-¹³C, ¹⁸O]- and [1-¹³C, ²H₂]-glycerol is described in which the ¹³C label is introduced using cyanide. The ¹⁸O label was introduced by a Pinner synthesis and reduction of the ester 5 allowed incorporation of the ²H labels.     

Long, narrow all-light atom guide

A 1-mm-diameter all-light atom guide capable of transporting ultracold atoms tens of centimeters with high efficiency is described. We made the atom tunnel, a dark hollow beam that is blue detuned from resonance, by passing a few tens of milliwatts of energy from a TEM(00) diode laser beam through an optical sequence composed of three axicons and a simple lens. We demonstrate transport of 10(8)Cs atoms approximately 20 cm with minimal heating. We show that it is possible for one to control the direction and speed of the atoms in the tunnel by varying the detuning of the tunnel beam.     

An Eulerian hybrid WENO centered-difference solver for elastic–plastic solids

We present a finite-difference based solver for hyper-elastic and viscoplastic systems using a hybrid of the weighted essentially non-oscillatory (WENO) schemes combined with explicit centered difference to solve the equations of motion expressed in an Eulerian formulation. By construction our approach minimizes both numerical dissipation errors and the creation of curl-constraint violating errors away from discontinuities while avoiding the calculation of hyperbolic characteristics often needed in general finite-volume schemes. As a result of the latter feature, the formulation allows for a wide range of constitutive relations and only an upper-bound on the speed of sound at each time is required to ensure a stable timestep is chosen. Several one- and two-dimensional examples are presented using a range of constitutive laws with and without additional plastic modeling. In addition we extend the reflection technique combined with ghost-cells to enforce fixed boundaries with a zero tangential stress condition (i.e. free-slip).