Search results for "indigo"

Applying the Techniques on Materials I

2012

The knowledge of the composition of the natural dye mixtures gives hints on appropriate procedures for restoration strategies. Identification of the dyes used, the establishment of their biological source, how they have been prepared, how these historical textiles were made, can provide important information. The dyestuffs used up to nineteenth century were either of plant (weld, madder, indigo, etc.) or animal origin (cochineal, shellfish, etc.) and belonged to various chemical types, such as flavonoids (yellow), anthraquinones (red) and indigoids (blue and violet). In this study microsamples (19) were examined from 11 Mevlana’s kaftans, dervishs’ dresses and dated from the thirteenth cent…

Sowing date, transplanting, plant density and nitrogen fertilization affect indigo production from Isatis species in a Mediterranean region of Spain

2006

Abstract The increasing interest in natural products from a renewable source has encouraged growers to reintroduce indigo-producing crops into the European agriculture. We studied agronomic conditions (sowing date, plant density, nitrogen fertilization, irrigation rate, seedling transplanting) influencing production of the blue pigment indigo, from Isatis tinctoria and I. indigotica crops in a Mediterranean region of Spain (Valencia). I. tinctoria was more suitable for cultivation in our climate conditions than I. indigotica . Indigo yield from Spanish I. tinctoria trials was greater than in Northern and Central Europe. Furthermore, indigo production was maintained when water and nitrogen s…

Square wave voltammetric determination of the redox state of a reversibly oxidized/reduced depolarizer in solution and in solid state

2012

Abstract Square wave voltammetric measurements allows for determining the composition of system containing a reversibly reducible/oxidable electroactive species in two oxidation states. The method is based on recording the ratio of reverse to forward peak currents. That ratio can be correlated with the molar fraction of the oxidized (or reduced) form of the depolarizer. The method was compared with cyclic voltammetric methods suggested in literature and it was tested using Fe ( CN ) 6 3 - / Fe ( CN ) 6 4 - in solution phase. Application to solid state systems is illustrated by the dehydroindigo/indigo couple in synthetic Maya Blue-type specimens prepared from indigo plus different clays whe…

Response to “C. Tsiantos, M. Tsampodimou, G.H. Kacandes, M. Sánchez del Río, V. Gionis, G.D. Chryssikos. Comment to the paper: Identification of indi…

2014

Natural Indigo from Isatis tinctoria L. for the Reassessment of Sicilian Crops - A Minireview

2013

Examples of xylochemistry: colorants and polymers

2017

Against the backdrop of modern sustainable chemistry and valorization of biomass for chemical raw materials, the syntheses of indigo dyes and polyamides as representatives of two classes of everyday chemical products based on xylochemicals are described. Wood-derived starting materials were transformed into functional materials using the principles of green chemistry to expand the scope of products gained from renewable resources. The indigo dyes were synthesized in a short, straightforward sequence starting from vanillin. Two polyamides, representatives of an important class of polymers, were obtained from 4-propylcyclohexanol, which is one of the longest known (and most abundant) hydrogen…

Textiles in blue : production, consumption and material culture in rural areas in early-nineteenth century Finland

2021

The article focuses on masculine consumption patterns and the production and dyeing of textiles in rural Finland in the early nineteenth century. It maintains that the rural consumption of textiles as well as individual choices and tastes evolved, and our selected examples of males’ wardrobes demonstrate that contemporary styles were followed. The article targets an era that can be regarded as a watershed: this was a time when mass production was in its infancy and craft production and self-sufficiency were still relevant to household economies. As the wealth of certain groups, particularly landed peasantry, increased, they began among other things to purchase and wear clothes dyed with imp…

Redox tuning and species distribution in Maya Blue-type materials: a reassessment.

2013

Maya Blue-type specimens prepared from indigo (1 wt %) plus kaolinite, montmorillonite, palygorskite, sepiolite, and silicalite are studied. Liquid chromatography with diode array detection, ultra-performance liquid chromatography coupled with mass spectrometry, and pyrolysis-silylation gas chromatography-mass spectrometry analyses of the extracts from these specimens combined with spectral and solid-state voltammetry, electrochemical impedance spectroscopy, and scanning electrochemical microscopy techniques provide evidence for the presence of a significant amount of dehydroindigo and isatin accompanying indigo and other minority organic compounds in all samples. Solid-state electrochemist…

Chromoendoscopy and narrow-band imaging compared with high-resolution magnification endoscopy in Barrett's esophagus.

2008

Background & Aims: The aim of this study was to compare magnified still images obtained with high-resolution white light endoscopy, indigo carmine chromoendoscopy, acetic acid chromoendoscopy, and narrow-band imaging to determine the best technique for use in Barrett's esophagus. Methods: We obtained magnified images from 22 areas with the 4 aforementioned techniques. Seven endoscopists with no specific expertise in Barretes esophagus or advanced imaging techniques and 5 international experts in this field evaluated these 22 areas for overall image quality, mucosal image quality, and vascular image quality. In addition, the regularity of mucosal and vascular patterns and the presence of abn…

Composition and Color of Maya Blue: Reexamination of Literature Data Based On the Dehydroindigo Model

2019

[EN] An analysis of literature data studying the composition and color of Maya blue (MB) type materials prepared from indigo, dehydroindigo, and different aluminosilicates, accompanied by new spectral data, is presented. After thermal treatment at above 100 degrees C, indigo-based specimens displayed Raman and UV-vis spectroscopic features common to those of equivalent dehydroindigo-based replicants, thus supporting the socalled dehydroindigo model (J. Phys. Chem. B 2006, 110, 6027-6039) in which the dehydroindigo/indigo ratio, increasing with temperature, is crucial to determine the color of MB and its variability. The current analysis supports the view of MB as a polyfunctional hybrid mat…