Benzanthrone derivatives are potential fluorescent probes for various chemical and biological environments. A mechanistic understanding of their photophysical properties is pivotal for designing an efficient fluorescence sensor based on the benzanthrone framework. In this study, we report on the effect of chemical substitution on the photophysical properties of two benzanthrone derivatives, namely, 3-(N'-methyl)-piperazino-7H-benzo[de]anthracen-7-one [Me-PBA] and 3-(N'-phenyl)-piperazino-7H-benzo[de]anthracen-7-one [Ph-PBA] in different solvents and solvent mixtures of varying polarities and proticities. Both benzanthrone derivatives show interesting solvent-dependent photophysical properties. Although both derivatives exhibit strong intramolecular charge transfer (ICT) characteristics in the excited state, the extent of the charge transfer is significantly influenced by the nature of the chemical substitution. Modulation of photophysical parameters as a function of solvent properties led us to propose that ICT is affected by solvent polarity and hydrogen bonding. From the viscosity effect, it is revealed that the weaker emission of Ph-PBA compared to Me-PBA in polar solvents is primarily due to the non-radiative torsional motion of the phenyl group in the former derivative. In protic solvents, intermolecular hydrogen bonding imparts strong non-radiative deactivation to both derivatives, thus rendering a weak fluorescence yield.
The change in photophysical properties of the organic molecule due to solvatochromic effect caused by different solvent environments at room temperature gives information about the dipole moments of 3-N-(N'-methylacetamidino)benzanthrone (3-MAB). The quantum yield, fluorescence lifetime of 3-MAB was measured in different solvents to calculate radiative and non-radiative rate constants. The results revealed that the excited state dipole moment (μ ) is relatively larger compared to the ground state dipole moment (μ ), indicating the excited state of the dye under study is more polar than the ground state and the same trend is noticed with theoretical calculations performed using the CAM-B3LYP/6-311+G(d,p) method. Further, the study on preferential solvation was carried out for 3-MAB dye in ethyl acetate-methanol solvent mixture. The fluorescence quenching method has been employed for the detection of dopamine using 3-MAB as fluorescent probe, using steady-state and time resolved methods at room temperature. The method enables dopamine in the micro molar range to be detected. Also, an attempt to verify the quenching process by employing different models has been tried. Various rate parameters are measured using these models, our results indicates the quenching process is diffusion limited.
This prospective study was analyzed in 23 patients who were allowed to do immediate weight bearing after uncemented total hip arthroplasty. Immediate mobilization shortened the hospital stay and facilitated early rehabilitation of hip. Immediate mobilization was started on postoperative Day 3 rather than Day 7 without any adverse consequences to the patients. A series of 23 elderly patients of age more than 60 years, who were diagnosed with conditions such as avascular necrosis of hip, non union of fracture neck of femur, trochanteric non union and rheumatoid arthritis, underwent uncemented total hip replacement and immediate mobilization was started in our hospital. Patients were evaluated by Harris Hip Scoring Scale. All ambulated patients had painless hip and the mean Harris Hip Score was 85. There were no incidence of stem subsidence, acetabular component loosening, and heterotrophic ossification. This data concluded that early intensive rehabilitation yielded faster attainment of short-term functional milestones in fewer days.
When developing software today, we still use old tools and ideas. Maybe it is time to start from scratch and try tools and languages that are more in line with how we actually want to develop software. The Go Programming Language was created at Google by a rather famous trio: Rob Pike, Ken Thompson and Robert Griesemer. Before introducing Go, the company suffered from their development process not scaling well due to slow builds, uncontrolled dependencies, hard to read code, poor documentation and so on. Go is set out to provide a solution for these issues. The purpose of this master’s thesis was to review the current state of the language. This is not only a study of the language itself but an investigation of the whole software development process using Go. The study was carried out from an embedded development perspective which includes an investigation of compilers and cross-compilation. We found that Go is exciting, fun to use and fulfills what is promised in many cases. However, we think the tools need some more time to mature.
The UV/Vis absorption and fluorescence characteristics of 3-cyano-7-hydroxycoumarin [CHC] and 7-amino-4-methyl-3-coumarinylacetic acid [AMCA-H] were studied at room temperature in several neat solvents and binary solvent mixtures of 1,4-dioxane/acetonitrile. The effects of solvent on the spectral properties are analyzed using single and multi-parameter solvent polarity scales. Both general solute/solvent interactions and hydrogen bond interactions are operative in these systems. The solvation of CHC and AMCA-H dyes in 1,4-dioxane/acetonitrile solvent mixtures has been studied. The solutes CHC and AMCA-H are preferentially solvated by acetonitrile and a synergistic effect is observed for both molecules in dioxane/acetonitrile solvent mixtures. In addition, using the solvatochromic method the ground- and the excited-state dipole moments of both the dyes were calculated. The ground- and excited-state dipole moments, absorption and emission maxima and HOMO-LUMO gap were also estimated theoretically using B3LYP/6-311+ G (d,p) level of theory in the gaseous phase, dioxane and acetonitrile solvents. Furthermore, changes in dipole moment values were also calculated using the variation of Stokes shift with the molecular-microscopic empirical solvent polarity parameter ( ETN). The observed excited-state dipole moments are larger than their ground-state counterparts, indicating a substantial redistribution of the electron densities in a more dipolar excited state for both coumarins investigated.
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