Contrast dependence of scattering profiles for poly(ethylene glycol) in water: Investigation by small-angle neutron scattering with 3He spin filter and small-angle x-ray scattering.

The small-angle neutron scattering (SANS) and small-angle x-ray scattering (SAXS) measurements were performed for deuterated and non-deuterated poly(ethylene glycol) (d-PEG and h-PEG, respectively) in D2O and a D2O/H2O mixed solvent (Mix) to compare the scattering profiles. To determine the coherent scattering intensity of SANS, a 3He spin filter was utilized. The scattering profiles determined by the SANS measurements were analyzed in terms of the wormlike chain model with touched beads along the contour of the chain. However, the SAXS profiles were not explained by the same model with uniform beads but with beads each consisting of a core and a shell having different electron densities. To explore the chain thickness determined from the SANS profile, the scattering intensities for different combinations of d-PEG/D2O, d-PEG/Mix, h-PEG/D2O, and h-PEG/Mix were also examined.

Analysis of Early Biomarkers Associated with the Development of Critical Respiratory Failure in Coronavirus Disease 2019 (COVID-19).

Certain biomarkers predict death due to acute respiratory distress syndrome in COVID-19 patients. We retrospectively analyzed biomarkers associated with time to mechanical ventilation for respiratory failure due to COVID-19 (time-to-mechanical ventilation) in 135 consecutive patients in our hospital. We analyzed biomarkers that were elevated immediately (at admission) and later (3 days after admission) using Cox proportional hazards regression analysis. Independent biomarkers of time-to-mechanical ventilation were high C-reactive protein (CRP), interleukin (IL)-6, and Krebs von den Lungen-6 (KL-6) concentrations at admission and elevated CRP, high-mobility group box-1 protein (HMGB-1), and d-dimer levels and low platelets 3 days after admission. Receiver operating characteristic analysis for detecting the association between independent biomarkers associated with time-to-event in multivariate analyses and the start of mechanical ventilation revealed that these biomarkers had area under the curve values higher than 0.700. The present study suggests that CRP was the only biomarker associated with time-to-mechanical ventilation both at admission and 3 days after admission. Moreover, IL-6 (an inflammatory cytokine), HMGB-1 (a late inflammatory mediator), and KL-6 (reflecting injury and/or remodeling of type II pneumocytes) were associated with outcomes in COVID-19 as reported previously. In conclusion, increased CRP, IL-6, KL-6, HMGB-1, and d-dimer levels and decreased platelet counts were associated with the start of mechanical ventilation due to COVID-19.