Hierarchically Porous Carbon Cloth–Polyaniline (CC–PANI) Composite Supercapacitor Electrodes with Enhanced Stability

In this work, hierarchically porous composites were prepared in the form of activated carbon cloth (CC) Busofit T–1–055 filled with an electrically conductive polymer, polyaniline (PANI), for use as pseudocapacitive electrodes of electrochemical supercapacitors (SCs). CC fibers have high nanoporosity and specific surface area, so it was possible to deposit (via the chemical oxidative polymerization of aniline) a significant amount of PANI on them in the form of a thin layer mainly located on the inner surface of the pores. Such morphology of the composite made allowed the combining of the high capacitive characteristics of PANI with the reversibility of electrochemical processes, high columbic efficiency and cyclic stability rather typical for carbon materials of double-layer SCs. The highest capacitance of composite electrodes of about 4.54 F/cm2 with high cyclic stability (no more than 8% of capacity loss after 2000 charge–discharge cycles with a current density of 10 A/cm2) and columbic efficiency (up to 98%) was achieved in 3 M H2SO4 electrolyte solution when PANI was synthesized from an aniline hydrochloride solution with a concentration of 0.25 M. Trasatti analysis revealed that 27% of specific capacitance corresponded to pseudocapacitance, and 73% to the double-layer capacitance

Stent-assisted coiling of acute ruptured cerebral aneurysms

The necessity of quick surgical treatment of acute ruptured cerebral aneurysms was demonstrated in large studies by the ISAT and ISUIA, which also proved the advantage of the endovascular method over the surgical one. Ballonassistence is widely used in treatment of aneurysms with wide neck and unfavorable vascular anatomy, but the radicality of the treatment is insufficient. The aim of this study was to demonstrate the efficacy and safety of stent-assisted embolization of «acute» cerebral aneurysms. Material and methods. A retrospective analysis of the treatment of 234 patients with «acute» cerebral aneurysms was carried out. Results. Only coils were used in 40.6 % of cases (n = 95), balloon-assistance, in 40.2 % of cases (n = 94), and stent-assistance, in 19.2 % of cases (n = 45). There were 11.5 % (n = 27) clinically significant complications. Total aneurysm occlusion (Raymond-Roy I) was achieved in 187 cases (79.9 %); the radicality at the control examination was 67.1 % (157 patients). Discussion. The radicality of the treatment with stents was slightly higher then with balloons and coils at the end of operation (84.4 %, n = 38 and 78.8 %, n = 149, p > 0.05), but it was significantly higher at the control examination (80.0 %, n = 36 and 60.8 %, n = 115, respectively, p <0.05). Also, we had no statistically significant difference of the complication rate in the «stent» and «no stent» groups; therefore, the clinical outcomes of endovascular treatment of cerebral aneurysms did not depend on the choice of treatment method. Conclusions. Intracranial stents allow achieving good results of the embolization of complex aneurysms in the acute period of intracranial hemorrhage without increasing the risk of surgical treatment

The efficiency of transvenous access for embolization of convexital cerebral arteriovenous malformations

Introduction. Convexital localization of cerebral arteriovenous malformations (AVM) is a good prognostic criterion for successful endovascular treatment. Difficulties begin in the final stages of large AVMs, in the transit nature of afferents. Transvenous embolization has been developed as an alternative to microsurgery and radiosurgery for a limited range of malformations. Materials, methods, results. January 2011 - December 2016, the National Medical Research Center treated 440 patients with cerebral arteriovenous malformations who underwent more than 1200 embolization sessions. From this number, a transvenous access to the AVM was performed in 43 patients. AVMs were localized in the cerebral cortex of 12 patients; in 2 of them (17 %) the transvenous embolization was the single treatment option; the rest of the patients required 2 to 4 preliminary transarterial staged embolizations. In the group, no lethal outcomes and significant persistent neurological deficit were recorded. Total deactivation was achieved in 9 patients (75 %); 2 patients (16.7 %) required microsurgical removal of residual AVM network; in 1 patient (8.3 %), radiosurgical treatment was performed. Discussion. Comparing the results of transvenous treatment of convexital malformations with an of patients treated with the classic transarterial technique, no statistically significant difference (p > 0.05) in morbidity and mortality was achieved. The total occlusion rate of transvenous embolization is significantly higher (p < 0.05). Conclusions. A gradual expansion of indications for the transvenous access increases the efficiency of surgical treatment of this pathology without significantly increasing the risks of adverse outcomes. This access should only be used in centers with significant experience of transarterial embolization