There are some technical difficulties in treating for a broad necked aneurysm and a higher incidence of recurrence. Because of these drawbacks, more innovative techniques for superior endovascular reconstructive treatment are required. We developed a novel covered stent employing electrospinning to deposit fine polyurethane (PU) fibers onto stents. An in vitro water leak test was designed and applied prior to animal testing to estimate the performance of covered stents and to determine the appropriate amount of PU fibers on a stent. Two tenths of a milligram of PU fibers proved to be sufficient to prevent water leakage. Then, the efficacy of the covered stents to that of bare stents was compared using 10 rabbits in which model aneurysms had been formed at the right common carotid artery by the elastase method. Angiographic evaluation on day 1 posttreatment (acute phase) revealed complete occlusion of the aneurysms and the patency of the parent arteries in animals treated with covered stents. At 10 days poststenting (subacute phase), the aneurysm neck was completely covered with neointimal layer as shown by scanning electron microscopic examination. The PU-covered stent holds promise as a device for treating cerebral aneurysms.

Fluorescent cellulose derivatives were synthesized by utilizing the carbazole group in order to induce optical and semi‐conducting properties. The PL spectra of these cellulose derivatives exhibit UV‐blue emissions at about 350–450 nm attributed to carbazole groups. Analyses of photoelectron spectra were also performed to determine IP values. The results of IP, UV‐vis and PL analyses were almost the same as those of PVK, while the PL intensity and efficiency of the cellulose derivatives were quite different. These compounds functioned as hole transporting materials of OLEDs. Devices using each of the derivatives showed different electronic behavior (current density‐voltage characteristics, EL spectra, etc.), indicating the importance of regioselectivity of the substituent group.

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