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Fluorescence Methods (fluorescence + methods)
Selected AbstractsDC conduction in bis(dimethylglyoximato)palladium(II) thin filmsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 8 2007A. A. Dakhel Abstract Bis(dimethylglyoximato)palladium (II) complex thin films of polycrystalline structure were prepared by sublimation in a vacuum at 140°C on p-Si substrates. After carrying out the characterisation of the prepared films by X-ray diffraction and X-ray fluorescence methods, Al-complex-Si MIS devices were fabricated. The constructed MIS structure was characterised by measuring the capacitance as a function of gate voltage at 1 MHz. The dependence of dc-current density on gate voltage and temperature in the range of 293 - 328 K of the MIS device was measured. It was found that the experimental data follow the trap-charge-limited space-charge-limited conductivity mechanism, from which the total concentration and the exponential energy distribution of the trap density were determined. In general, the measured quantities suggest that the conduction can be realised by thermally assisted hopping between localised states bundled in a very narrow band lying energetically near the mobility band edge. Moreover, results show that it is possible to use a film of the complex in applications of low-k dielectric material. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Tissue response to polyglycolide, polydioxanone, polylevolactide, and metallic pins in cancellous bone: An experimental study on rabbitsJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 8 2006Harri Pihlajamäki Abstract The purpose of this study was to investigate, qualitatively and histoquantitatively, the tissue response of rabbit femur cancellous bone to polyglycolide (PGA), polydioxanone (PDS), polylevolactide (PLLA), and stainless steel pins under identical conditions. Eighty knees in 50 rabbits were operated on by inserting bioabsorbable pins (PGA, PDS, or PLLA) together with metallic Kirschner wire in 60, and two metallic Kirschner wires alone in 20 knees, while 20 knees served as intact controls. Follow-up times were 3, 6, 12, 24, and 52 weeks. Cancellous bone tissue response to implants was studied using histological, histomorphometrical, microradiographical, and oxytetracycline fluorescence methods. Residual fragments of PGA and PDS were seen at 24 weeks. Complete degradation of these polymers had taken place before 52 weeks. No signs of degradation of the PLLA pins were observed within the entire follow-up period. The osteoid formation surfaces at tissue implant-interface were statistically larger in all test groups as compared to intact controls. The number of macrophages at tissue implant-interfaces increased in all bioabsorbable implant specimens until 6 weeks, and with PGA until 12 weeks. No differences in the osseous response emerged when comparing groups of bioabsorbable implants with each other or with stainless steel group. Bioabsorbable pins and metallic Kirschner wires evoked an osteoconductive response in the cancellous bone surrounding implant, but the response intensity between implants displayed no differences. This suggests a simple, nonspecific walling-off new-bone front type of response. Consequently, the polymers possessed no specific osteostimulatory or osteoinhibitory properties. Within the follow-up, no significant differences in biocompatibility between the implants appeared, and no frank inflammatory foreign-body reactions occurred. The small-volume pins obviously did not exceed the local tissue tolerance and clearing capacity of the bone. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:1597,1606, 2006 [source] A Systematic Review of the Performance of Methods for Identifying Carious LesionsJOURNAL OF PUBLIC HEALTH DENTISTRY, Issue 4 2002James D. Bader DDS Abstract This systematic review evaluates evidence describing histologically validated performance of methods for identifying carious lesions. A search identified 1,407 articles, of which 39 were included that described 126 assessments of visual, visuaVtactile, radiographic (film and digital), fiber optic transillumination, electrical conductance, and laser fluorescence methods. A subsequent update added four studies contributing 10 assessments. The strength of the evidence was judged to be poor for all applications, signifying that the available information is insufficient to supporf generalizable estimates of the sensitivity and specificity of any given application of a diagnostic method. The literature is problematic with respect to complete reporting of methods, variations in histological validation methods, the small number of in vivo studies, selection of teeth, small numbers of examiners, and other factors threatening both internal and external validity. Future research must address these problems as well as expand the range of assessments to include primary teeth and root surfaces. [source] Sensitive determination of protein based on the fluorescence enhancement effect of terbium (III),epinephrine,protein,sodium dodecylsulfate systemLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 6 2009Yumei Guo Abstract It was found that the fluorescence of Tb3+,epinephrine (E) complex can be enhanced by both bovine serum albumin (BSA) and sodium dodecylsulfate (SDS), and stabilized by ascorbic acid (AA). It is considered that the fluorescence enhancement of the Tb3+,E,BSA,AA,SDS system originates not only from the hydrophobic microenvironment provided by BSA,SDS, but also from the energy transfer from BSA to Tb3+ in this system. Therefore, a new fluorescence method for the determination of protein concentrations as low as 1.3 × 10,9 g mL,1 BSA is established using Tb3+,epinephrine complex as probe. The method has been applied for the determination of BSA and human serum albumin in actual samples, and the results obtained are satisfactory. Compared with other fluorescence methods, this method is simpler and more sensitive for the determination of protein. The mechanism of the fluorescence enhancement of the system is studied in detail. Copyright © 2009 John Wiley & Sons, Ltd. [source] Effects of sulfur limitation on photosystem II functioning in Chlamydomonas reinhardtii as probed by chlorophyll a fluorescencePHYSIOLOGIA PLANTARUM, Issue 2 2006Taras K. Antal Chlorophyll fluorescence methods were applied to probe in vivo photosystem II (PSII) function in Chlamydomonas reinhardtii grown in sulfur-depleted media under aerobic conditions. The rates of oxygen evolution and dark reduction decreased during a 24-h incubation in sulfur-deficient medium, while the respiration rate increased. The analysis of chlorophyll fluorescence induction curves suggests that electron transport was perturbed on both the acceptor and donor sides of PSII. Light-induced violaxanthin de-epoxidation and non-photochemical fluorescence quenching were suppressed, owing to dark accumulation of zeaxanthin. Also sulfur-deprived cells showed elevated concentrations of violaxanthin and lutein. Sulfur deprivation stimulated a pronounced (three- to four-fold) increase in chlorophyll a fluorescence intensity (parameters Fo and Fm), probably due to greater light absorption by carotenoids and changes in the excitation energy transfer and deactivation in PSII of C. reinhardtii. [source] | ||||||||||