2 research outputs found
Ammonia as Proton Conducting Medium Confined in Porous Materials
Molecular confinement within a limited space induces unique behaviour not seen in bulk systems. In
particular, the proton diffusion in conducting medium under confined conditions
is significantly affected by the surrounding environment.H2O, efficient conducting medium,
confined in hydrophobic channels forms unique clusters allowing rapid
diffusion, whereas confined NH3, having a similar degenerate system
(Fig. 1a), has not been reported. Herein, we show NH3-mediated
proton conduction in microporous metal–organic frameworks (MOFs), MIL-53(Al)
functionalized with (-COOH)2, -NH2, -OH and -H. Anhydrous
NH3 gas is trapped in the pore by proton donation of frameworks and
forms hydrogen bonding networks exhibiting a remarkably enhanced proton
conductivity. The crystallographic analysis and solid-state NMR clarify the
veiled proton diffusion mechanism and unique dynamic behaviour of confined NH3.<br /
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