“We report on near normal infrared reflectivity spectra of similar to 550 nm thick films made of cosputtered transition metal nanograins and SiO2 in a wide range of metal fractions. Co0.85(SiO2)(0.15), with conductivity well above the percolation threshold has a frequency and temperature behavior according
to what it is find in conducting metal oxides. NSC23766 order The electron scattering rate displays a unique relaxation time characteristic of single type of carriers experiencing strong electron-phonon interactions. Using small polaron fits we identify those phonons as glass vibrational modes. Ni-0.61(SiO2)(0.39), with a metal fraction closer to the percolation threshold, undergoes a metal-nonmetal transition at similar to 77 K. Here, as it is suggested by the scattering rate nearly AZD6094 solubility dmso quadratic dependence, we broadly identify two relaxation times (two carrier contributions) associated to a Drude mode and a midinfrared overdamped band, respectively. Disorder induced, the midinfrared contribution drives the phase transition by thermal electron localization. Co-0.51(SiO2)(0.49) has the reflectivity of an insulator with a distinctive band at similar to 1450 cm(-1) originating in electron promotion, localization, and defect induced polaron formation.
Angle dependent oblique reflectivity of globally insulating Co-0.38(SiO2)(0.62), Fe0.34(SiO2)(0.66), and Ni-0.28(SiO2)(0.72), reveals a remarkable resonance at that band threshold. We understand this as due to the excitation by normal to the film electric fields of defect localized electrons in the metallic nanoparticles. At higher oblique angles, this localized nanoplasma couples to SiO2 longitudinal optical Berreman phonons resulting in band peak softening reminiscent to the phonon behavior undergoing strong electron-phonon interactions. Singular to a globally
insulating phase, we believe that this resonance might be a useful tool for tracking metal-insulator phase transitions in inhomogeneous materials. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3126485]“
“BACKGROUND Hypertrophic scars and keloids may complicate wound healing secondary to trauma or surgery. A variety of treatment regimens have been used for treatment of keloids. OBJECTIVE To compare 5-fluorouracil (5-FU) tattooing and intralesional steroid for treatment of keloids. METHODS In this find more 44-week, double-blind, clinical trial, 40 patients were randomized into two study groups. Patients in group 1 were given intralesional triamcinolone acetonide (TAC), and patients in group 2 were treated with 5-FU tattooing; both groups received treatment every 4 weeks for 12 weeks. Lesions were assessed for erythema, pruritus, height, surface, and induration at baseline (initiation of treatment) and at weeks 4, 8, 12, 20, 28, 36, and 44. All patients had complete blood count, liver function tests, and renal function tests before treatment and at week 20.