Search results for "Dye"
showing 10 items of 577 documents
Heritage-making: Written Texts in the Transmission of Traditional Knowledge of Natural Dyeing
2022
Natural dyeing is an element of intangible cultural heritage which is gaining new relevance today. Heritage-making as a set of purposeful activities has become an object of interest for researchers relatively recently, and this study is reflective of that. The paper aims to focus on natural dyeing as a component of cultural heritage, its documentation process, and how written texts have influenced the living tradition of natural dyeing. One of the sources for the study was ethnographic material, which provides insight into the little researched tradition of natural dyeing. To understand how the tradition was described and explained, Latvian press publications on natural dyeing were evaluate…
Impact of hydroxy and octyloxy substituents of phenothiazine based dyes on the photovoltaic performance
2013
Two novel organic dyes containing hydroxy and octyloxy substituents onto a phenothiazine skeleton were synthesized and their effects on the photovoltaic performance were studied. Hydroxy acts as an ancillary anchoring unit along with the carboxylic group, while the phenothiazine modified moiety acts as an electron donor. The photophysical and electrochemical studies revealed that maximum absorbance of the dye with the hydroxy group in the solution was blue shifted and its band gap increased, indicating that donor acceptor strength was reduced as compared to the octyloxy substituted dye. Furthermore, electron lifetime of the organic dye with the hydroxy moiety was shorter due to smaller resi…
Synthesis and photovoltaic performance of dihydrodibenzoazepine-based sensitizers with additional lateral anchor
2013
Three novel metal-free organic dyes with dihydro-5H-dibenzo[b,f]azepine as a donor and cyanoacrylic acid as an anchoring unit were designed as an innovative linear skeleton of D-D-pi-A type of organic dyes. The conversion efficiency of the derived dye-sensitized solar cells is moderate. Among them, the dye with a hydroxy group as an additional anchoring moiety exhibited the highest UV-Vis absorption with a maximum molar extinction coefficient of 24,136 M-1 cm(-1) at lambda(max) = 458 nm and the best photovoltaic performance with an overall power conversion efficiency of 4.88%, while the dye with a carboxy group as an additional anchoring moiety exhibited the lowest conversion efficiency (4.…
Characterization of triphenylamino-based polymethine dyes
2013
In this high-technology application, age functional dyes especially polymethine dyes have captured much attention of the researchers due to their immense potential for high-tech uses. Polymethine dyes show promising absorption spectra in the visible range, which can be easily exploited for the use of written text copying, photographic imaging, or photothermographic recording materials. Keeping this in mind, our research is composed of an investigation of two triphenylamino-based polymethine dyes, a known polymethine dye 3 and a new one polymethine dye 5, which have been synthesized by the reaction of 4-(diphenylamino) benzaldehyde 2 and 4,4′-(phenylazanediyl) dibenzaldehyde 4 with 4,4′-viny…
Chromo-Fluorogenic Detection of Nerve-Agent Mimics Using Triggered Cyclization Reactions in Push-Pull Dyes
2010
A family of azo and stilbene derivatives (1-9) are synthesized, and their chromo-fluorogenic behavior in the presence of nerve-agent simulants, diethylchlorophosphate (DCP), diisopropylfluorophosphate (DFP), and diethylcyanophosphate (DCNP) in acetonitrile and mixed solution of water/acetonitrile (3:1 v/v) buffered at pH 5.6 with MES, is investigated. The prepared compounds contain 2-(2-N,N-dimethylaminophenyl)ethanol or 2-[(2-N,N-dimethylamino)phenoxy]ethanol reactive groups, which are part of the conjugated pi-system of the dyes and are able to give acylation reactions with phosphonate substrates followed by a rapid intramolecular N-alkylation. The nerve-agent mimic-triggered cyclization …
Synthesis of novel organic-based fluorophores – Implementation to the design of fluorogenic enzyme substrates based on the principle of in situ synth…
2020
Detection and fluorescence imaging of biologic systems requires the implementation of efficient, robust and easy-to-use tools. Conventional fluorogenic probes currently used in microbiology lack efficiency since they are based on the single chemical modification of a fluorophore bearing an optically tunable reactive group, which often leads to incomplete fluorescence quenching. The main goal of my Ph.D thesis was to develop novel fluorogenic enzymatic substrates based on the "covalent assembly" principle. This approach also named "in situ synthesis" is based on the use of domino reactions to form a fluorescent moiety starting from a "caged" non-fluorescent molecule. In our case, the bioanal…
Binding of a fluorescent dansylcadaverine-substance P analogue to negatively charged phospholipid membranes.
2000
Abstract We have investigated the binding of a new dansylcadaverine derivative of substance P (DNC-SP) with negatively charged small unilamellar vesicles composed of a mixture of phosphatidylcholine (PC) and either phosphatidylglycerol (PG) or phosphatidylserine (PS) using fluorescence spectroscopic techniques. The changes in fluorescence properties were used to obtain association isotherms at variable membrane negative charges and at different ionic strengths. The experimental association isotherms were analyzed using two binding approaches: (i) the Langmuir adsorption isotherm and the partition equilibrium model, that neglect the activity coefficients; and (ii) the partition equilibrium m…
Efficacy of 595- and 1319-nm pulsed dye laser in the treatment of acne vulgaris: a narrative review
2020
Acne is one of the commonest problems of adolescence with almost half of the patients experiencing persistence into adulthood. Pulsed dye lasers (PDL) with wavelengths of 585 and 595 nm targeting hemoglobin have been used for the treatment of this condition and its sequelae. Recent introduction of PDL with a higher wavelength of 1319 nm has been reported to offer some benefit to acne patients. We reviewed the literature on the use of 595-nm and 1319-nm PDL in the management of acne. A PubMed literature search for search terms "pulsed dye laser," "acne laser therapy," "light therapy for acne," "595 nm and acne," "1319 nm and acne" was done. Studies, series and case reports were included. The…
Polymorphonuclear leukocyte membrane fluidity and cytosolic Ca2+ concentration in diabetes mellitus.
1998
We evaluated polymorphonuclear membrane (PMN) fluidity in 32 subjects with type 1 diabetes mellitus, 38 subjects with type 2 diabetes mellitus and 38 normal control subjects, by marking intact and unstimulated PMN cells with the fluorescent probe 1-[4-(trimethylamino)phenyl]-6-phenyl-1,3,5-hexatriene (TMA-DPH). We also evaluated PMN cytosolic Ca2+ content by marking intact and unstimulated PMN cells with the fluorescent probe Fura 2-AM. PMN membrane fluidity differentiated normal subjects from type 1 and 2 diabetic subjects. The PMN cytosolic Ca2+ concentration did not discriminate type 1 and 2 diabetic subjects from normal control subjects. No statistical correlation was found between PMN …
Cytosolic Ca2+Content and Membrane Fluidity of Platelets and Polymorphonuclear Leucocytes in Diabetes Mellitus
1995
Considering the role played by platelets and leucocytes in diabetic disease and keeping in mind the strong correlation between functional and metabolic aspects that characterizes this clinical condition, we evaluated, in two groups of diabetics, respectively the platelet and polymorphonuclear (PMN) cytosolic Ca2+ content (employing the fluorescent probe Fura 2-AM) and membrane fluidity (using the fluorescent probe TMA-DPH and considering the fluorescence polarization degree, inversely related to the membrane fluidity). From the obtained results, it is evident that the platelet cytosolic Ca2+ content does not distinguish normals from diabetics of type 1 and 2; the platelet membrane fluidity …