Background The exact epidemiology of acute aortic dissection, including cases of out-of-hospital cardiopulmonary arrest, is unclear. We aimed to investigate the incidence and characteristics of acute aortic dissection in patients with out-of-hospital cardiopulmonary arrest transferred to our institution and validate the related factors to out-of-hospital cardiopulmonary arrest in Stanford type A acute aortic dissection. Methods We retrospectively reviewed the acute-phase computed tomography data of patients with out-of-hospital cardiopulmonary arrest who visited our hospital between 1 January 2015 and 31 December 2017. Results Among 1011 consecutive patients with out-of-hospital cardiopulmonary arrest, excluding those aged 17 years and younger and exogenous out-of-hospital cardiopulmonary arrest, such as suicide and trauma, 934 underwent computed tomography examination and 71 (7.6%) were diagnosed with acute aortic dissection: 66 with Stanford type A and five with type B acute aortic dissection (out-of-hospital cardiopulmonary arrest group). Seventy-five patients without out-of-hospital cardiopulmonary arrest with Stanford type A acute aortic dissection visited our institution during the same period (non-out-of-hospital cardiopulmonary arrest group). Age, incidence of massive bloody pericardial effusion and massive intrathoracic haemorrhage were significantly higher in the out-of-hospital cardiopulmonary arrest than in the non-out-of-hospital cardiopulmonary arrest group (78 ± 8 years, 72.7% and 24.2% vs. 70 ± 13 years, 26.7% and 1.3%, respectively; all P < 0.01). These variables were independently related to out-of-hospital cardiopulmonary arrest. Conclusions There may be more patients with acute aortic dissection with out-of-hospital cardiopulmonary arrest than previously thought. Aortic rupture into the pericardial space or thoracic cavity is the major cause of out-of-hospital cardiopulmonary arrest in these cases. Non-contrast computed tomography can be used to diagnose acute aortic dissection in patients with out-of-hospital cardiopulmonary arrest. Our study is one of a few to evaluate the real circumstances surrounding acute aortic dissection and its epidemiology.

Ferromagnetic shape memory alloys (FSMAs) such as NiMnGa are expected to be new practical actuator materials with high driving frequency by magnetic field and large strain due to the shape memory effect (SME). However, the brittleness and poor workability of FSMAs, especially at a polycrystalline state, are serious problems and should be improved for a practical use. From this viewpoint a smart composite has been designed by a combination of a polymer matrix and FSMA particles (FSMAP), and a systematic investigation has been done for a NiMnGa-FSMAP/epoxy smart composite. This paper summarizes the design concept and some experimental results of the smart composite. It is pointed out that the single-crystal NiMnGa-FSMAP are easily made by mechanical crush due to the brittleness of FSMAs, and microstructural control is also possible by applying magnetic field during curing. Experimental study revealed that the NiMnGa-FSMAP/epoxy smart composites exhibit both tensile ductility and SME, and that shape memory properties become improved by decreasing particle size of FSMAP. It is concluded that the FSMAP/polymer smart composite has a large potential to be a new practical actuator material. q

The extremely low sticking probability of iron inhibits the formation of metallic iron grains around evolved stars.

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