Synthesis of P- and N-doped carbon catalysts for the oxygen reduction reaction via controlled phosphoric acid treatment of folic acid.

Herein, we synthesized P- and N-doped carbon materials (PN-doped carbon materials) through controlled phosphoric acid treatment (CPAT) of folic acid (FA) and probed their ability to catalyze the oxygen reduction reaction (ORR) at the cathode of a fuel cell. Precursors obtained by heating FA in the presence of phosphoric acid at temperatures of 400-1000 °C were further annealed at 1000 °C to afford PN-doped carbon materials. The extent of precursor P doping was maximized at 700 °C, and the use of higher temperatures resulted in activation and increased porosity rather than in increased P content. The P/C atomic ratios of PN-doped carbon materials correlated well with those of the precursors, which indicated that CPAT is well suited for the preparation of PN-doped carbon materials. The carbon material prepared using a CPAT temperature of 700 °C exhibited the highest ORR activity and was shown to contain -C-PO2 and -C-PO3 moieties as the major P species and pyridinic N as the major N species. Moreover, no N-P bonds were detected. It was concluded that the presence of -C-PO2 and -C-PO3 units decreases the work function and thus raises the Fermi level above the standard O2/H2O reduction potential, which resulted in enhanced ORR activity. Finally, CPAT was concluded to be applicable to the synthesis of PN-doped carbon materials from N-containing organic compounds other than FA.

Warped graphitic layers generated by oxidation of fullerene extraction residue and its oxygen reduction catalytic activity.

Carbon-based oxygen reduction reaction (ORR) catalysts are regarded as a promising candidate to replace the currently used Pt catalyst in polymer electrolyte fuel cells (PEFCs); however, the active sites remain under discussion. We predicted that warped graphitic layers (WGLs) are responsible for the ORR catalytic activity in some carbon catalysts (i.e., carbon alloy catalysts (CACs)). To prove our assumption, we needed to use WGLs consisting of carbon materials, but without any extrinsic catalytic elements, such as nitrogen, iron, or cobalt, which effectively enhance ORR activity. The present study employed a fullerene extraction residue as a starting material to construct WGLs. The oxidation of the material at 600 °C exposed the WGLs by removing the surrounding amorphous moieties. Transmission electron microscopy (TEM) observations revealed the formation of WGLs by oxidation treatment at 600 °C in an O2/N2 stream. Extending the oxidation time increased the purity of the WGL phase, but also simultaneously increased the concentration of oxygen-containing surface functional groups as monitored by temperature programmed desorption (TPD). The specific ORR activity increased with oxidation up to 1 h and then decreased with the intensive oxidation treatment. Correlations between the specific ORR activity and other parameters confirmed that the development of the WGL and the increase in the O/C ratio are the competing factors determining specific ORR activity. These results explain the maximum specific ORR activity after 1 h of oxidation time. WGLs were found to lower the heat of adsorption for O2 and to increase the occurrence of heterogeneous electron transfer.

[Effectiveness and role of lamotrigine in the paradigm shift towards new antiepileptic drugs: a therapeutic strategy proposed after an investigation of a large number of cases at a single hospital].

Lamotrigine (LTG) has been recognized as one of the best newer antiepileptic drugs (AEDs) used in developed countries since 1991. A retrospective study was carried out to evaluate the efficacy, adverse reactions, and other peculiarities of LTG. Two hundred and eighty-one patients with epilepsy, aged 16 or more, were treated with LTG between December 2008 and December 2012 at the Seirei Hamamatsu General Hospital. One hundred and forty patients were found to be eligible to evaluate the effectiveness of LTG. Of them, 100 patients had localized epilepsy, and 40 patients had generalized epilepsy. Seventy-five out of these 140 (53.6%) patients obtained seizure freedom following LTG use, and 24 patients (17.1%) showed more than 50% seizure reduction, which indicates that a total of 99 patients (70.7%) were good responders. A seizure reduction of less than 50% was seen in 8 patients (5.7%), whereas 30 patients (21.4%) did not display any obvious seizure reduction. Three patients (2.1%) showed a worsening of seizure frequency. Patients with idiopathic generalized epilepsy such as juvenile myoclonic epilepsy showed satisfactory results. Many good responders were also patients with stroke or brain tumor. The number of concomitant AEDs used demonstrated a more distinctive feature. Monotherapy without any other AEDs was used in 20 patients. LTG was used as an add-on with 1 concomitant AED in 59 patients (42.1%) and as an add-on with 2 concomitant AEDs in 37 patients (26.4%). Thus, a large number of patients (68.6%) underwent early add-on treatment. LTG as an add-on in concert with concomitant AEDs contributed to the excellent results in terms of seizure reduction observed in this study. LTG administration requires established titration, particularly to prevent drug eruption. Over 60% of the patients were treated by slower titration than that used in the established titration method. However, seizure freedom was accomplished within 1-5 weeks from the beginning of LTG treatment with doses much lower than 200 mg/day, which indicated the effectiveness of low-dose LTG in the early phase of treatment. The average maintenance dose was 162.7 mg/day; however, half of the patients maintained their dose at more than 200 mg/day. The continuation rate was 77.2%. The main reasons for withdrawal were dissatisfaction with drug effectiveness and drug eruption. However, the incidence of drug eruption was only in 15 out of 281 (5.3%) patients, which is similar to previously reported rates. Therefore, LTG is an effective and safe AED. Moreover, it is a promising drug for promoting a paradigm shift towards newer AEDs. LTG administration as a first add-on AED is strongly recommended to obtain excellent results and to maintain good compliance with the epilepsy treatment course.

Intramedullary tuberculoma with syringomyelia.

Intramedullary tuberculoma with syringomyelia is rare. We treated a woman with back pain and weakness of the left leg that had slowly progressed for more than 30 years. Radiologic evaluation demonstrated a crescent-shaped calcification at the level of the C6 vertebra, and syringomyelia from C7 to T9. Laminectomy and syringosubdural shunt placement were performed, and a tuberculoma was removed. Back pain resolved after the operation, and mobility was facilitated. We recommend surgery for intrathecal tuberculoma with syringomyelia even when the course has been prolonged with no active tuberculous lesion.