Synthesis and characterization of novel polyurethanes based on N¹,N⁴‐bis[(4‐hydroxyphenyl)methylene]succinohydrazide hard segment

Abstract

Objective The protective effect of HLA–DRB1 alleles on the development of rheumatoid arthritis (RA) is poorly understood. The aim of this study was to perform a meta‐analysis of 4 European populations to investigate which HLA–DRB1 alleles are associated with protection in anti–citrullinated protein antibody (ACPA)–positive RA and ACPA‐negative RA. Methods Data for >2,800 patients and >3,000 control subjects for whom information on HLA–DRB1 typing and ACPA status was available were collected from 4 European countries: Norway, Sweden, The Netherlands, and Spain. The odds ratios (ORs) and 95% confidence intervals (95% CIs) associated with the different HLA–DRB1 alleles were analyzed in a combined meta‐analysis focused on protective alleles and classifications. The analysis of ACPA‐positive RA was stratified for the shared epitope (SE) alleles, to correct for skewing due to this association. Results In ACPA‐positive RA, the only alleles that conveyed protection after stratification for SE were HLA–DRB1*13 alleles (OR 0.54 [95% CI 0.38–0.77]). The protective effect of the allele classifications based on the DERAA and D70 sequences was no longer present after exclusion of DRB1*13 (for D70, OR 0.97 [95% CI 0.75–1.25]), indicating that DRB1*13, rather than the DERAA or D70 sequence as such, is associated with protection. Among the DRB1*13 alleles, only DRB1*1301 was associated with protection (OR 0.24 [95% CI 0.09–0.59]). Protection appeared to follow a north‐to‐south gradient, with the strongest association in northern European countries. In ACPA‐negative RA, there were no robust associations with HLA–DRB1 alleles. Conclusion Our data do not support any of the classifications of protective alleles and indicate that protection against ACPA‐positive RA is predominantly associated with HLA–DRB1*1301.

Preparation and characterization of novel polyurethanes containing 4,4′-{oxy-1,4-diphenyl bis(nitromethylidine)}diphenol schiff base diol

“…Overall, in the current study, DSC data are in good agreement with our earlier reports [21,22,29,30].…”

“…The emission spectra from these diols and PUs have appeared around 364-375 nm and 462-485 nm, respectively [29]. From the absorption and emission spectra, it can be concluded that there is no significant difference in ODBNMD and hard-segmented PUs and that the observed absorption and emission spectral data are in close agreement with the previous reports [29,30].…”

“…The aromatic ring protons occur in the region 6.30-8.60 ppm [30]. due to imines and urethane carbonyl carbons, respectively [30]. UV-visible electronic and florescence spectra of diphenol diol and hard-segmented PUs have been recorded in DMF solvent at ambient temperature.…”

Silk‐inspired polyurethane containing GlyAlaGlyAla tetrapeptide. II. physical properties and structure

“…Absorption peaks observed around 265 nm are attributed to the p-p* transition of the localized benzenoid ring. 43,44 From the absorption spectra, it is concluded that there is no significant difference in the three PUs of this study. The absorption peak of BDO-extended PU (265 nm) exhibited a slight red shift in wavelength compared with that of Dow BPU (263 nm), while the absorption peak of silk-inspired PU (266 nm) exhibited a farther slight red shift in wavelength compared with that of BDO-extended PU (265 nm).…”

Synthesis and characterization of novel Schiff base polyurethanes

“…Previous articles from our laboratories [1][2][3][4][5] -bis[(4-hydroxyphenyl)methylene]-succinohydrazide as hard segments. As a continuation of those studies, we present here the preparation schemes and characterization of eight novel types of PUs, based on similar, previously developed diols, 1,2 that were produced through changes in the position of the hydroxyl groups and the use of different aliphatic dialdehydes instead of diamine units as hard segments of the PUs.…”