Search results for "Fluorescence"
showing 10 items of 2463 documents
Advanced Glycation End Products: New Clinical and Molecular Perspectives
2021
Diabetes mellitus (DM) is considered one of the most massive epidemics of the twenty-first century due to its high mortality rates caused mainly due to its complications; therefore, the early identification of such complications becomes a race against time to establish a prompt diagnosis. The research of complications of DM over the years has allowed the development of numerous alternatives for diagnosis. Among these emerge the quantification of advanced glycation end products (AGEs) given their increased levels due to chronic hyperglycemia, while also being related to the induction of different stress-associated cellular responses and proinflammatory mechanisms involved in the progression …
Effect of plasticizers (water and glycerol) on the diffusion of a small molecule in iota-carrageenan biopolymer films for edible coating application.
2006
Translational diffusion of a fluorescein probe has been measured in iota-carrageenan edible films containing different amounts of glycerol (0, 15, 30, and 45%), using fluorescence recovery after photobleaching (FRAP) experiments. The effects of this plasticizer as well as the plasticizing effect of water on the diffusion of fluorescein have been studied in this edible coating mainly composed of natural biopolymer. Diffusion coefficients of about 10(-13) m2 s(-1) have been measured in these films for water activity (aw) lower than 0.7. Above this water content threshold, fluorescein translational diffusion coefficient increases up to 10(-12) m2 s(-1). Another interesting information obtained…
Porphyrin-bile acid conjugates: from saccharide recognition in the solution to the selective cancer cell fluorescence detection.
2008
This paper describes the preparation and use of conjugates of porphyrins and bile acids as ligands to bind to tumor expressed saccharides. Bile acid-porphyrin conjugates were tested for recognition of saccharides that are typically present on malignant tumor cells. Fluorescence microscopy, in vitro PDT cell killing, and PDT of subcutaneous 4T1 mouse tumors is reported. High selectivity for saccharide cancer markers and cancer cells was observed. This in vivo and in vitro study demonstrated high potential use for these compounds in targeted photodynamic therapy.
GFP-mut2 Proteins in Trehalose-Water Matrixes: Spatially Heterogeneous Protein-Water-Sugar Structures
2007
We report investigations on the properties of nanoenvironments around single-GFP-mut2 proteins in trehalose-water matrixes. Single-GFPmut2 molecules embedded in thin trehalose-water films were characterized in terms of their fluorescence brightness, bleaching dynamics, excited state lifetime, and fluorescence polarization. For each property, sets of approximately 100-150 single molecules have been investigated as a function of trehalose content and hydration. Three distinct and interconverting families of proteins have been found which differ widely in terms of bleaching dynamics, brightness, and fluorescence polarization, whose relative populations sizably depend on sample hydration. The r…
Analyzing Protein-Protein Spatial-Temporal Dependencies from Image Sequences Using Fuzzy Temporal Random Sets
2008
Total Internal Reflection Fluorescence Microscopy (TIRFM) allows us to image fluorescenttagged proteins near the plasma membrane of living cells with high spatial-temporal resolution. Using TIRFM imaging of GFP-tagged clathrin endocytic proteins, areas of fluorescence are observed as overlapping spots of different sizes and durations. Standard procedures to measure protein-protein colocalization of dual labeled samples threshold the original graylevel images to segment areas covered by different proteins. This binary logic is not appropriate as it leaves a free tuning parameter which can influence the conclusions. Moreover, these procedures rely on simple statistical analysis based on corre…
Determination of Mercury in Milk by Cold Vapor Atomic Fluorescence: A Green Analytical Chemistry Laboratory Experiment
2011
Green analytical chemistry principles were introduced to undergraduate students in a laboratory experiment focused on determining the mercury concentration in cow and goat milk. In addition to traditional goals, such as accuracy, precision, sensitivity, and limits of detection in method selection and development, attention was paid to the evaluation of green parameters of the analytical methods. Milk samples were evaluated by cold vapor atomic fluorescence spectrometry (CV-AFS) and the wastes were minimized by co-precipitation with Fe(III).
Hydrophobicity of bacteria Zymomonas mobilis under varied environmental conditions
2007
Abstract Changes in the cell surface hydrophobicity (CSH) of bacteria Zymomonas mobilis 113S were examined in response to varied environmental conditions (temperature and phase of growth, concentration or type of carbon source, the presence of amphiphilic compounds). The values of CSH were elevated with a decreased growth rate over the time of cultivation up to 20–22% at the stationary phase. CSH values increased proportionally with the growth of cultivation temperature and concentration of carbon source (glucose or sucrose) or amphiphilic compound (aliphatic alcohols, Tween80) in the medium. Replacement of sucrose by glucose and the presence of Tween20 in the growth medium resulted in redu…
Embryo Aneuploidy Screening for Unexplained Recurrent Miscarriage: A Minireview
2005
Problem: The aim of this study was to investigate the incidence of chromosomal abnormalities in unexplained recurrent miscarriage (RM) patients and assess the role of pre-implantation genetic diagnosis (PGD) in preventing subsequent pregnancy loss and improving pregnancy outcome. Method of Study: Pre-implantation genetic diagnosis was performed in 241 RM cycles and in 35 cycles in patients undergoing PGD for sex-linked diseases (control group). Chromosomes 13, 16, 18, 21, 22, X and Y were analysed by fluorescence in situ hybridization. Results: The implantation and pregnancy rates in RM patients were 26.4 and 36.5% versus 20.6 and 29.0% in the control group, respectively. The percentage …
A Chemosensor Bearing Sulfonyl Azide Moieties for Selective Chromo-Fluorogenic Hydrogen Sulfide Recognition in Aqueous Media and in Living Cells
2014
A simple chemodosimeter based on a sulfonyl azide dye (1-Az), which displayed a highly selective response toward hydrogen sulfide anion in mixed aqueous media, was synthesised and characterised. Addition of hydrogen sulfide to acetonitrile/HEPES 1:1 solutions of 1-Az induced a clear colour change from red-orange to yellow, which was easily detected by the naked eye, and by an enhancement in the emission intensity. Other common anions, thiol-containing biomolecules and oxidants did not induce any noticeable colour or fluorescence modulation in the probe. The chemodosimeter also showed a good sensitivity, with limits of detection of 11.91 and 0.63 μM by using UV/Vis or fluorescence measuremen…
Dzelzs jonu saturoša hidroksilapatīta iegūšana un analīze
2016
Dzelzs jonus saturoša hidroksilapatīta iegūšana un analīze. Margarita Š., zinātniskais vadītājs doc., Ancāne I. Bakalaura darbs, 46 lpp., 17 attēli, 6 tabulas, 32 literatūras avoti, 2 pielikumi. Latviešu valodā. Darbā ir veikta dzelzs jonus saturošu hidroksilapatītu sintēze, kvalitatīvā un kvantitatīvā analīze. Apkopota literatūras informācija par hidroksilapatītu īpašībām, to sintēzes iespējām un izmantošanu. Aprakstītas ķīmiskās analīzes metodes, kuras var izmantot metāla jona noteikšanai dažādos paraugos. Eksperimentālajā daļā veikta tīra HAp un FeHAp sintēze ar dažādu dzelzs saturu hidroksilapatītā. Iegūto hidroksilapatītu kvalitatīvais sastāvs noteikts izmantojot, pulvera rentgendifrak…