Exciton energy states and photoluminescence spectra of the strained-layer ZnS-ZnSe superlattices

Excitonic photoluminescence spectra in the ZnS-ZnSe strained-layer superlattices with imperfect heterointerfaces were studied experimentally. It is shown that the energy states of excitons in these structures are affected both by interface imperfections and internal strain caused by the lattice mismatch between the semiconductors composing the superlattice layers.     

Titanium-boride eutectic materials: Structure of titanium-rich Ti-Ge-B alloys and phase equilibria at crystallization temperatures

Phase equilibria in the Ti-TiB₂-Ti₅Ge₃ region of the Ti-Ge-B system are experimentally investigated at melting/solidification temperatures using x-ray diffraction, metallography, EMPA, and differential thermal analysis. The phase diagram is presented as projections of solidus and liquidus surfaces and a vertical section at 7.5 at.% B. __________ Translated from Poroshkovaya Metallurgiya, Vol. 46, No. 3–4 (454), pp. 62–71, 2007.     

Residual stresses in the phase components of spark coatings of tungsten and titanium carbides

The X-ray diffraction method is used to study the stressed structural state of spark coatings formed on U8 steel as a result of treatment with T15K6 hard-alloy electrodes. The residual stresses formed in different phase components have different values and signs. Subsequent laser heating decreases compressive and tensile stresses. In the austenitic interlayer of the steel substrate, the residual stresses relax almost completely due to the decrease in the specific volume of the phase in the course of the α → γ transformation. __________ Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 41, No. 5, pp. 115–118, September–October, 2005.     

Mathematical Modeling of the Monotonic and Cyclic Loading Processes

Strength of Materials - Based on experimental studies of specimens of 12Kh18N10T stainless steel under a rigid (strain-controlled) deformation process, which includes a sequence of monotonic and...     

A digital predistorter for wireless transmitters

A novel digital baseband predistorter with improved reduction of spectral regrowth is proposed and investigated. The improvements are achieved by using a proposed predistortion technique and extended power amplifier (PA) fundamental‐frequency modeling. The digital baseband predistortion (DPD), known for its simplicity of realization, low cost and integrability; however, it suffers from poor linearizing performances. We incorporate baseband iterative injection of in‐band distortion components into the baseband DPD to enhance the nonlinearity compensation. General formulas for the fundamental‐frequency output of a PA with n‐order nonlinearity and recursive formulas for calculating the injected components for different number of iterations are developed. The proposed iterative digital baseband predistorter is verified experimentally with a wireless PA and measured results are presented to demonstrate feasibility of the proposed concept. The spectral regrowth suppression of 20 dB is achieved for a 3.5 MHz digitally modulated signal. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.     

Novel hydrophilic bis(1,2,3-triazolyl)fluorenyl probe for in vitro zinc ion sensing

A hydrophilic bis(1,2,3-triazolyl)fluorene derivative was synthesized as a multi-photon-absorbing, zinc-ion-sensing fluorescent probe. The fluorescence response was approximately five-fold greater in presence of Zn(2+), resulting in a large binding constant (1 × 10(9)) for a 1:2 ligand to zinc complex. A four-fold increase in the two-photon absorption cross section was achieved upon binding Zn(2+). In vitro two-photon fluorescence microscopy imaging revealed a significant fluorescence increase upon introduction of Zn(2+) into HeLa cells and reversible Zn(2+) binding, demonstrating the potential of this probe for zinc ion sensing.     

Opioid Receptors and Protonation-Coupled Binding of Opioid Drugs

Opioid receptors are G-protein-coupled receptors (GPCRs) part of cell signaling paths of direct interest to treat pain. Pain may associate with inflamed tissue characterized by acidic pH. The potentially low pH at tissue targeted by opioid drugs in pain management could impact drug binding to the opioid receptor, because opioid drugs typically have a protonated amino group that contributes to receptor binding, and the functioning of GPCRs may involve protonation change. In this review, we discuss the relationship between structure, function, and dynamics of opioid receptors from the perspective of the usefulness of computational studies to evaluate protonation-coupled opioid-receptor interactions.