OBJECTIVES Although respiratory exposures have been the primary concern with isocyanates, skin exposure also can occur and may contribute to sensitization and asthma. Methodologies to assess isocyanate skin exposure in the workplace are limited and skin exposure data scarce. The goals of this study were (i) to evaluate and validate the isocyanate colorimetric indicators against a quantitative a...

Citation: Wachiralurpan S, Sriyapai T, Areekit S, Sriyapai P, Augkarawaritsawong S, Santiwatanakul S and Chansiri K (2018) Rapid Colorimetric Assay for Detection of Listeria monocytogenes in Food Samples Using LAMP Formation of DNA Concatemers and Gold Nanoparticle-DNA Probe Complex. Front. Chem. 6:90. doi: 10.3389/fchem.2018.00090 Rapid Colorimetric Assay for Detection of Listeria monocytogene...

A colorimetric method using a tetrazolium compound, 3,4,5-dimethylthiozalil-(1 or 2),2,5-diphenyltetrazolium bromide (TTBr), was developed for studying the growth activity of yeast-phase Histoplasma capsulatum. Materials extracted in phosphate buffer, pH 7.0, from cells at different stages of growth reduced TTBr. Colorimetric changes were correlated with enzymatic activity. Under standardized c...

BACKGROUND Visual assessment of cerebrospinal fluid (CSF) for xanthochromia (yellow color) is practiced by the majority of laboratories worldwide as a means of diagnosing intracranical bleeds. METHODS Colorimetric and spectrophotometric analysis of CSF samples for recognizing the presence of bilirubin either in low concentrations or in the presence of hemolysed blood. RESULTS The experiment...

LLE Review, Volume 73 59 Ever since cholesteric liquid crystals (CLC’s) were discovered in 1888,1 CLC colors have been noted for their qualitative vividness and luminosity;2 however, there have been few quantitative colorimetric studies examining CLC’s as colorants. We will describe how CLC’s produce color, what colorimetric studies have been done on them, and how we have extended and improved ...

Episulfides were determined by a simple colorimetric assay using 4-(p-nitrobenzyl)-pyridine, which has been used previously for the detection and analysis of epoxides, organophosphates, and other alkylating agents. With episulfides, absorbance was directly proportional to concentration up to an absorbance of at least 1.0. No interference was observed with a variety of non-episulfide sulfur-cont...

The design, synthesis and physical evaluation of 1, a visible colorimetric 'naked eye' pyridyl based bis-amidothiourea sensor for anions, is described. This charge neutral sensor gives rise to significant changes in the absorption spectra upon interactions with several important biological anions such as AMP and ADP in 4:1 DMSO-H(2)O solution, while ATP was not detected. These colorimetric chan...

In order to find a fast, high efficient determination method of Organophosphorus Pesticides (OPPs) residue because OPPs widely used in crops pest control fields in China are causing fearful risks for environment as well as animals and human health, traditional and advanced determination methods were discussed in the study. Based on the spectrum analysis technology combined colorimetric OPPs res...

Biosensors are analytical devices that have found a variety of applications in medical diagnostics, food quality control, environmental monitoring and biodefense. In recent years, functional nucleic acids, such as aptamers and nucleic acid enzymes, have shown great potential in biosensor development due to their excellent ability in target recognition and catalysis. Deoxyribozymes (or DNAzymes)...

A new nonlinear dimensionality reduction method for multi-spectral images was presented to solve the problem brought by high dimensionality of multi-spectral images during color reproduction. Firstly, according to the characteristics of human visual system, the CIE standard observer color matching functions were weighted to the source spectral reflectance and then a principal component analysis...