Unexpected Crossover in the kinetics of mutarotation in the supercooled region : the role of H-bonds

Intra- and intermolecular studies on the molten L-sorbose have been carried out at variable temperature conditions to determine the crosover temperature (Tc). In addition, isothermal time-dependent FTIR and Raman measurements were performed to probe the pace of mutarotation and activation energy of this reaction in the studied saccharide, which varied from 53–62 kJ/mol up to 177–192 kJ/mol below and above Tc, respectively. To explain the change in activation barrier for the mutarotation a complementary analysis using difference FTIR spectra collected around Tc = 365 K in the hydroxyl region has been done. It was found that the alteration of kinetic parameters and molecular dynamics around Tc are strictly related to the variation in the strength of H-bonds which above Tc are significantly weaken, increasing the freedom of rotation of functional groups and movement of individual molecules. That phenomenon most likely affects the proton transfer, underlying molecular mechanism of mutarotation, which may lead to the significant increase in activation barrier. The new insight into a molecular aspect of the mutarotation around Tc has created an opportunity to better understanding the relationship between physics of condensed matter and the potential role of H-bonds dynamics on the progress of the chemical reaction in highly viscous systems

The application of spatially restricted geometries as a unique route to produce well-defined poly(vinyl pyrrolidones) via free radical polymerisation

We report, for the first time, the metal-free green synthesis of linear poly(vinyl pyrrolidone) (PVP) homopolymers of molecular weight higher than 100 kg mol and narrow dispersities via thermal and photo-induced free radical polymerisation carried out within alumina nanoporous membranes acting as >nanoreactors>.K. K. and M. T. are thankful for financial support from the Polish National Science Centre within SONATA Bis project (Dec. no. 2015/18/E/ST4/00320). M. T. is thankful for financial support from the Foundation for Polish Science (FNP). L. L.-B. and C. M. acknowledge MINECO for financial support (MAT2017-83014-C2-2-P)

Herpesviruses, inflammatory markers and incident depression in a longitudinal study of Detroit residents

BACKGROUND: Depression is predicted to become the leading cause of disability worldwide by 2030 and moreover, socioeconomic inequalities in depression persist. Herpesviruses, which are more prevalent among socioeconomically disadvantaged populations, subject to stress-induced reactivation and are associated with increased levels of pro-inflammatory cytokines implicated in the etiology of depression, may serve as novel risk factors for depression onset. METHODS: Data are from individuals in the Detroit Neighborhood Health Study tested for herpes simplex virus-1 (HSV-1) and cytomegalovirus (CMV) seropositivity/Immunoglobulin G (IgG) antibody levels (N=263) as well as interleukin-6 (IL-6) (N=245) and C-reactive protein (CRP) (N=236) levels and assessed for incident depression via the Patient Health Questionnaire-9. Linear and logistic regression models were used to examine associations between pathogen seropositivity/IgG antibody levels, pro-inflammatory markers and incident depression over approximately one-year of follow-up. RESULTS: For every one unit increase in CMV IgG antibody level, the odds of incident depression increased by 26% and individuals with IgG antibody levels in the highest quartile had over three times greater odds of incident depression (odds ratio 3.87, 95% confidence interval 1.47, 10.19), compared to those in the lower three quartiles. Neither CMV or HSV-1 seropositivity nor HSV-1 IgG antibody level were associated with IL-6 or CRP levels at Wave 1, nor were IL-6 or CRP levels associated with incident depression at Wave 2. CONCLUSIONS: Further examination of the biological pathways linking CMV and depression are warranted