Search results for "Colori"
showing 10 items of 281 documents
Colorimetric gas detection by the varying thickness of a thin film of ultrasmall PTSA-coated TiO2 nanoparticles on a Si substrate
2017
Financial support from the Estonian Research Council (IUT2-25, PUT170, PUT1096, PUT748, PUTJD680), the Estonian Centre of Excellence in Research Projects “Advanced materials and high-technology devices for sustainable energetics, sensorics and nanoelectronics” TK141 (2014-2020.4.01.15-0011), “Emerging orders in quantum and nanomaterials” TK134 and the Development Fund of the University of Tartu, are all gratefully acknowledged.
A fast heuristic for solving the D1EC coloring problem
2010
In this paper we propose an efficient heuristic for solving the Distance-1 Edge Coloring problem (D1EC) for the on-the-fly assignment of orthogonal wireless channels in wireless as soon as a topology change occurs. The coloring algorithm exploits the simulated annealing paradigm, i.e., a generalization of Monte Carlo methods for solving combinatorial problems. We show that the simulated annealing-based coloring converges fast to a sub optimal coloring scheme even for the case of dynamic channel allocation. However, a stateful implementation of the D1EC scheme is needed in order to speed-up the network coloring upon topology changes. In fact, a stateful D1EC reduces the algorithm’s convergen…
A heuristic for fast convergence in interference-free channel assignment using D1EC coloring
2010
This work proposes an efficient method for solving the Distance-1 Edge Coloring problem (D1EC) for the assignment of orthogonal channels in wireless networks with changing topology. The coloring algorithm is performed by means of the simulated annealing method, a generalization of Monte Carlo methods for solving combinatorial problems. We show that the simulated annealing-based coloring converges fast to a suboptimal coloring scheme. Furthermore, a stateful implementation of the D1EC scheme is proposed, in which network coloring is executed upon topology changes. The stateful D1EC is also based on simulated annealing and reduces the algorithm’s convergence time by one order of magnitude in …
Ionic-liquid doped polymeric composite as passive colorimetric sensor for meat freshness as a use case.
2020
Abstract A composite membrane containing 1,2-naphthoquinone-4-sulfonic acid sodium salt (NQS) embedded in an ionic liquid (IL)- polydimethylsiloxane (PDMS)- tetraethyl orthosilicate (TEOS)- SiO2 nanoparticles (NPs) polymeric matrix is proposed. The selected IL was 1-methyl-3-octylimidazolium hexafluorophosphate (OMIM PF6). It is demonstrated that ILs chemical additives of PDMS influenced the sol-gel porosity. The sensor analytical performance for ammonia atmospheres has been tested as a function of sampling time (between 0.5 and 312 h), temperature (25 °C and 4 °C) and sampling volume (between 2L and 22 mL) by means of diffuse reflectance measurements and sensor photos, which can be registe…
Recent developments in the use of viability dyes and quantitative PCR in the food microbiology field.
2013
The increase in foodborne outbreaks highlights the need for rapid, sensitive and specific methods for food safety monitoring, enabling specific detection and quantification of viable foodborne pathogens. Real-time PCR (qPCR) combined with the use of viability dyes, recently introduced, fulfils all these requirements. The strategy relies on the use of DNA-binding molecules such as propidium monoazide (PMA) or ethidium monoazide (EMA) as sample pretreatment previous to the qPCR. These molecules permeate only membrane-compromised cells and have successfully been applied for different types of foodborne pathogens, including bacteria and viruses. Moreover, those dyes have been explored to monito…
Fluconazole susceptibility of Italian Candida dabliniensis clinical isolates determined by reference and simplified tests
2001
Candida dubliniensis ia an opportunistic pathogen mainly associated with oral candidiasis in human immunodeficiency virus (HIV)-infected individuals. We recently recovered the first Italian clinical isolates of C. dubliniensis from the oral cavities of seven HIV-seropositive subjects. The in vitro susceptibility to fluconazole (FLCZ) of these isolates was determined according to the National Committee for Clinical Laboratory Standards (NCCLS) M27-A broth microdilution method for yeasts. All seven isolates of C. dubliniensis were susceptible to FLCZ (MICs < or =0.5 microg/ml). Results of this reference method were compared to those obtained with simplified tests, more adapted to routine eval…
Colorimetric susceptibility testing for Aspergillus fumigatus: comparison of menadione-augmented 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazo…
1996
Two colorimetric methods that use Alamar Blue or 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) for assaying the in vitro activities of antifungal agents have been described. We report that both tests performed similarly when the antifungal activity of amphotericin B against Candida albicans was determined. However, only the MTT test generated interpretable data when Aspergillus fumigatus was used.
Triggering dissymmetry in achiral dye molecules by chiral solvents: Circular dichroism experiments and DFT calculations
2011
The electronic circular dichroism spectra of achiral product “Lumogen F Red” (ROT-300) in four different chiral solvents are recorded at different temperatures. DFT calculations allow to identify two enantiomeric conformers for ROT-300. In vacuo they are equally populated; in chiral solvents one enantiomer prevails. Thermodynamic quantities involved in the chiral preference are derived. Chirality, 2011. © 2011 Wiley-Liss, Inc.
Impact of local compressive stress on the optical transitions of single organic dye molecules
2012
The ability to mechanically control the optical properties of individual molecules is a grand challenge in nanoscience and could enable the manipulation of chemical reactivity at the single-molecule level. In the past, light has been used to alter the emission wavelength of individual molecules or modulate the energy transfer quantum yield between them. Furthermore, tensile stress has been applied to study the force dependence of protein folding/unfolding and of the chemistry and photochemistry of single molecules, although in these mechanical experiments the strength of the weakest bond limits the amount of applicable force. Here, we show that compressive stress modifies the photophysical …
Single-Molecule FRET Reveals a Cooperative Effect of Two Methyl Group Modifications in the Folding of Human Mitochondrial tRNALys
2011
Summary Using a combination of advanced RNA synthesis techniques and single molecule spectroscopy, the deconvolution of individual contributions of posttranscriptional modifications to the overall folding and stabilization of human mitochondrial tRNA Lys is described. An unexpected destabilizing effect of two pseudouridines on the native tRNA folding was evidenced. Furthermore, the presence of m 2 G10 alone does not facilitate the folding of tRNA Lys , but a stabilization of the biologically functional cloverleaf shape in conjunction with the principal stabilizing component m 1 A9 exceeds the contribution of m 1 A alone. This constitutes an unprecedented cooperative effect of two nucleotide…