Correlation between the Closure Time of Patent Ductus Arteriosus in Preterm Infants and Long-Term Neurodevelopmental Outcome.

In patent ductus arteriosus (PDA) in preterm infants, the relationship between treatment timing and long-term developmental prognosis remains unclear. The purpose of this study was to clarify the relationship between the age in days when ductus arteriosus closure occurred and long-term development. Preterm infants with a birth weight of less than 1500 g who were admitted to our NICU over a period of 9 years (2011-2019) and were diagnosed with PDA were included. A new version of the K-type developmental test for corrected ages of 1.5 and 3 years was used as an index of development. The relationship between the duration of PDA and the developmental index was evaluated using Pearson's correlation coefficient, and multiple regression analysis was performed. Development quotient (DQ) at the ages of 1.5 and 3 years showed a correlation with the PDA closure date and the standard deviation (SD) value of the term birth weight. Multiple regression analysis showed a positive correlation of the DQ at 1.5 and 3 years with the SD value of the term birth weight and a negative correlation with the PDA closure date. In addition, a stronger correlation was found in the "posture/motor" sub-item at 3 years. On the other hand, the analysis including preterm infants without PDA showed that preterm infants with PDA closure on the 6th day or later after birth had a significantly lower 3-year-old DQ than preterm infants with a PDA exposure within 5 days. In conclusion, it is suggested that the decrease in cerebral blood flow due to PDA in preterm infants has an adverse effect on long-term neurodevelopment. Appropriate interventions, including surgical treatment for PDA in preterm infants without delay, ideally within 5 days of birth, may be effective in improving the developmental prognosis.

High-pressure glass formation of a series of 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide homologues.

We investigated the stability of the liquid phase of a series of 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([Cnmim][TFSI]) homologues with different alkyl chain lengths for 3 ≤ n ≤ 10 at room temperature. We found that all [Cnmim][TFSI] samples (n = 3-10) formed a glassy state when pressure was applied. Intriguingly, the glass transition pressure (pg) slightly increases up to n = 5, reaches a plateau at n ≧ 8, and increases again at n = 10. This is completely different from the high-pressure glass formation of [Cnmim][BF4], where the pg decreases as n increases. We discussed the local structural changes occurring in [Cnmim][TFSI] in view of the conformational changes of the cation and anion, and small-angle X-ray scattering data. It seems that [Cnmim][TFSI] is resistant to external pressure and retains its local liquid structure by conformational adjustments of the cation and anion.