Borderline Range Determined Using Data From Validation Study of Alternative Methods for Skin Sensitization: ADRA, IL-8 Luc Assay, and EpiSensA.

Most predictive models that use alternatives to animal experiments divide judgements into two classes with a cutoff value for each model. However, if the results of alternative methods are close to the cutoff values, the true result may be ambiguous because of variability in the data. Therefore, the OECD GL497 uses a judgement method that establishes a borderline range (BR) around a cutoff value using a statistical method.

Applicability of amino acid derivative reactivity assay (4 mM) for the prediction of skin sensitization by combining multiple alternative methods to evaluate key events.

The amino acid derivative reactivity assay (ADRA) is an alternative method for evaluating key event 1 (KE-1) in the skin sensitization mechanism included in OECD TG442C (OECD, 2021). Recently, we found that ADRA with a 4-mM test chemical solution had a higher accuracy than the original ADRA (1 mM). However, ADRA (4 mM) has yet to be evaluated using integrated approaches to testing and assessment (IATA), a combination of alternative methods for evaluating KE.

Improving predictive capacity of the Amino acid Derivative Reactivity Assay test method for skin sensitization potential with an optimal molar concentration of test chemical solution.

The Amino acid Derivative Reactivity Assay (ADRA) is a convenient and effective in chemico test method for assessing covalent binding of test chemicals with protein-derived nucleophilic reagents as a means of predicting skin sensitization potential. Although the original molar-concentration approach to ADRA testing was not suitable for testing multiconstituent substances of an unknown composition, a weight-concentration approach that is suitable for such substances was developed, which also led to the realization that test chemical solutions prepared to molar concentrations higher than the original 1 mM would reduce false negative results as well as enhance predictive capacity. The present study determined an optimal molar-concentration that achieves even higher predictive capacity than the original ADRA.

The Role of Linkers in the Excited-State Dynamic Planarization Processes of Macrocyclic Oligothiophene 12-Mers.

Linkers adjoining chromophores play an important role in modulating the structure of conjugated systems, which is bound up with their photophysical properties. However, to date, the focus of works dealing with linker effects was limited only to linear π-conjugated materials, and there have been no detailed studies on cyclic counterparts. Herein we report the linker effects on the dynamic planarization processes of π-conjugated macrocyclic oligothiophene 12-mers, where the different ratio between ethynylene and vinylene linkers was chosen to control the backbone rigidity.