Unusual Molecular and Supramolecular Structures of Chiral Low Molecular Weight Organogelators with Long Perfluoroalkyl Chains

Gels composed of low molecular weight gelators (LMWGs) are fascinating research targets from the viewpoint of applications because their functionalities are easily modified by designing their molecular structures. Some reliable gelator design approaches have been developed. However, new classes of molecular gelators are sometimes discovered unexpectedly, suggesting that there remain unknown aspects about gelators. To obtain knowledge regarding gelation and crystallization ability, the crystal structure of <i>N,N</i>′-diperfluorooctanoyl-(1<i>R</i>,2<i>R</i>)-1,2-diaminocyclohexane (<i>RR</i>-CF8), which is a derivative of 1,2-diaminocyclohexane, one of the most famous LMWGs, was investigated in addition to the vibrational circular dichroism (VCD) measurements. The crystal structure was solved from powder X-ray diffraction patterns because recrystallization of <i>RR</i>-CF8 afforded no suitable single crystals for single crystal X-ray diffraction measurement. Two unusual structural features were confirmed. One is that the perfluoroalkyl chain (PFC) of <i>RR</i>-CF8 forms a pseudoracemic helix, or a mixture of right- (<i>P</i>) and left-handed (<i>M</i>) helices, while elsewhere, PFCs generally have one-handed helicity. The other is that an oxygen atom of one of the amide groups is free of hydrogen bonds, reducing the stability of one-dimensional hydrogen-bonded assemblies. These unique structural features let us propose the reasonable explanations for the gelation and crystallization ability of <i>RR</i>-CF8. Furthermore, a factor of environment-dependent chirality inversion of <i>RR</i>-CF8 supermolecules was clarified by combining X-ray crystallography and solid-state VCD spectroscopy

National trends in the outcomes of subarachnoid haemorrhage and the prognostic influence of stroke centre capability in Japan: retrospective cohort study

Objectives To examine the national, 6-year trends in in-hospital clinical outcomes of patients with subarachnoid haemorrhage (SAH) who underwent clipping or coiling and the prognostic influence of temporal trends in the Comprehensive Stroke Center (CSC) capabilities on patient outcomes in Japan.Design Retrospective study.Setting Six hundred and thirty-one primary care institutions in Japan.Participants Forty-five thousand and eleven patients with SAH who were urgently hospitalised, identified using the J-ASPECT Diagnosis Procedure Combination database.Primary and secondary outcome measures Annual number of patients with SAH who remained untreated, or who received clipping or coiling, in-hospital mortality and poor functional outcomes (modified Rankin Scale: 3–6) at discharge. Each CSC was assessed using a validated scoring system (CSC score: 1–25 points).Results In the overall cohort, in-hospital mortality decreased (year for trend, OR (95% CI): 0.97 (0.96 to 0.99)), while the proportion of poor functional outcomes remained unchanged (1.00 (0.98 to 1.02)). The proportion of patients who underwent clipping gradually decreased from 46.6% to 38.5%, while that of those who received coiling and those left untreated gradually increased from 16.9% to 22.6% and 35.4% to 38%, respectively. In-hospital mortality of coiled (0.94 (0.89 to 0.98)) and untreated (0.93 (0.90 to 0.96)) patients decreased, whereas that of clipped patients remained stable. CSC score improvement was associated with increased use of coiling (per 1-point increase, 1.14 (1.08 to 1.20)) but not with short-term patient outcomes regardless of treatment modality.Conclusions The 6-year trends indicated lower in-hospital mortality for patients with SAH (attributable to better outcomes), increased use of coiling and multidisciplinary care for untreated patients. Further increasing CSC capabilities may improve overall outcomes, mainly by increasing the use of coiling. Additional studies are necessary to determine the effect of confounders such as aneurysm complexity on outcomes of clipped patients in the modern endovascular era