The thermal decompositions of carbamates. IV. The ethyl N?methyl?carbamate system

Ethyl N? methylcarbamate decomposes thermally over the temperature range of 600–650 K by competing first-order reactions, one forming methylamine, carbon dioxide, and ethylene, the other forming methyl isocyanate and ethanol. The first-order rate constants are described in S^{? 1} units by the equations where R = 1.986 cal/deg mol. The appareance of sym? dimethylurea among the products raised the possibility of gas-phase transesterifications. These were ruled out by the study of the reactions of sym-dimethylurea at 604 K which showed its behavior to be well explained by the rapid decomposition in the gas phase which is reversed in the condensation stage in the analysis.     

Synthesis and anti-cancer activity of dinuclear platinum(II) complexes containing bis(thioalkyl)dicarba-closo-dodecaborane(12) ligands

A series of novel, dinuclear (2,2':6',2'-terpyridine)platinum(ii) complexes containing bis(thioalkyl)-dicarba-closo-dodecaborane(12)(carborane) ligands were prepared and characterised, and their preliminary anti-cancer characteristics have been determined in vitro; the complexes are the first examples of bis-intercalator complexes containing a boron-rich carborane cage.     

Assessment of evolution of loss on ignition matter during heating of iron ores

Ironmaking involves reduction of iron ores to metallic iron using coke, coal or gas as reductants. Although different iron ore reduction processes exist, prior to each reduction type, commonly, the hydroxyl and clay materials present in the iron ores undergo decomposition as a first stage. The mass loss during decomposition of these materials is termed as Loss on Ignition (LOI). The aim of this work is to apply a computer aided thermoanalytical technique to evaluate five different iron ore types during decomposition of the LOI matter and determine associated decomposition temperature ranges and heats of reactions. Fourier Transform Infrared (FTIR) spectroscopy and thermogravimetric analysis (TG) were also incorporated to support the analysis interpretation. Three distinctive temperature ranges of decomposition of iron ore LOI matter were detected. The first region was associated with dehydration of the hygroscopic moisture at a temperature range between 100 and 150 °C. The second region occurred at a temperature range between 260 and 425 °C during which strongly bonded water was released and the OH groups associated with primarily iron oxyhydroxides were fractured. The third range, which occurred at a temperature range of 530 and 605 °C, was related to decomposition of the aluminosilicate clay materials.     

Metamaterial-based source and scattering enhancements: From microwave to optical frequencies

A brief review of metamaterial applications to source and scattering problems in the microwave and optical frequency regimes is given. Issues associated with modelling these systems are discussed. Electrically small radiating and scattering systems are emphasized. Single negative, double negative, and zero-index versions of these metamaterial-based systems are introduced that provide a means to manipulate their efficiency, bandwidth, and directivity characteristics.     

DECREASED HOST CELL REACTIVATION OF UV-IRRADIATED ADENOVIRUS 5 BY FIBROBLASTS FROM COCKAYNE'S SYNDROME PATIENTS

Abstract— Over a period of 5 years, we performed 29 experiments in which survival curves of UV-irradiated adenovirus were determined using fibroblast strains from 10 normal persons and from 7 persons having Cockayne's syndrome. In all of these, the survival of UV-irradiated adenovirus 5 was less when assayed using monolayers of fibroblasts from Cockayne's syndrome patients than from normal persons. Survival curves using normal fibroblasts were, within error, straight lines on a log survival vs. linear fluence plot. Survival curves obtained using Cockayne's syndrome fibroblasts showed 2 components: an initial sensitive component, reflecting the behavior of approx. 75% of the infected cells, followed by a component having normal sensitivity. In the 28 experiments that were considered reliable, 58 curves were done using Cockayne's fibroblasts, 41 using normal human fibroblasts. Although experimental variation was encountered, there was no individual case in which sensitivity as measured using Cockayne's was equal to (or less than) the sensitivity measured using normal fibroblasts.     

Impact of strong localization of the incident power density on the nano-amplifier characteristics of active coated nano-particles

Resonant, active coated nano-particles (CNPs) have been advocated as effective nano-amplifiers and nano-lasers. When it is properly designed to be in its super-resonant state, an electrically small active CNP captures significantly more of the incident field energy than its physical size suggests is possible. The corresponding enhancement of its extinction cross section is correlated with the concentration of the local field energy into its gain region. This energy localization can be visualized with the behavior of the flow lines of the Poynting vector field in the neighborhood of the CNP. Strong expulsion of the optical power generated from the interaction of the captured incident field energy with the gain medium creates an intense scattered field. As the interactions between the scattered field and the exciting plane wave increase, optical vortices form in the neighborhood of the active CNP. Gain depletion eventually occurs when the increase in the effective gain sufficiently detunes the resonance. A simple model for the gain enhancement effects observed in active CNPs is proposed that relates the enhanced effective size of the CNP caused by the field localization to the required gain necessary to achieve its super-resonant state. A comparison of the metal-covered, gain core, active CNP studied previously to the experimentally realized gain-impregnated silica-covered metal “SPASER” suggests that the active CNP design would require significantly less gain while offering a much larger enhancement of the incident field. Proposed modifications of both geometries that augment the field localization suggest further reductions in the gain values needed to achieve significant amplification of the output signal.