Effect of Surface Modification for Carbon Cathode Materials on Charge–Discharge Performance of Li-Air Batteries

Li-air batteries have attracted considerable attention as rechargeable secondary batteries with a high theoretical energy density of 11,400 kWh/g. However, the commercial application of Li-air batteries is hindered by issues such as low energy efficiency and a short lifetime (cycle numbers). To overcome these issues, it is important to select appropriate cathode materials that facilitate high battery performance. Carbon materials are expected to be ideal materials for cathodes due to their high electrical conductivity and porosity. The physicochemical properties of carbon materials are known to affect the performance of Li-air batteries because the redox reaction of oxygen, which is an important reaction for determining the performance of Li-air batteries, occurs on the carbon materials. In this study, we evaluated the effect of the surface modification of carbon cathode materials on the charge–discharge performance of Li-air batteries using commercial Ketjenblack (KB) and KB subjected to vacuum ultraviolet (VUV) irradiation as cathodes. The surface wettability of KB changed from hydrophobic to hydrophilic as a result of the VUV irradiation. The ratio of COOH and OH groups on the KB surface increased after VUV irradiation. Raman spectra demonstrated that no structural change in the KB before and after VUV irradiation was observed. The charge and discharge capacities of a Li-air battery using VUV-irradiated KB as the cathode decreased compared to original KB, whereas the cycling performance of the Li-air battery improved considerably. The sizes and shapes of the discharge products formed on the cathodes changed considerably due to the VUV irradiation. The difference in the cycling performance of the Li-air battery was discussed from the viewpoint of the chemical properties of KB and VUV-irradiated KB.     

Association between weight status and recreational drug abuse in Korean adolescents

The purpose of this study was to investigate the relationship between weight status and recreational drug use in Korean adolescents. A total of 72,399 adolescent students (38,152 boys and 34,247 girls) from the middle first to high third grade participated in the 5^th Korea Youth Risk Behaviour Web-based Survey (KYRBWS-V) project in 2009. They were assessed for body mass index (BMI) and recreational drug abuse. The associations between BMI and recreational drug use were examined using multivariable logistic regression analysis after adjusting for the covariate variables of age, smoking frequency and cigarette consumption, frequency of alcohol consumption and severe alcohol intoxication, amount of alcohol consumed, parents’ education level, economic status, sedentary activities during the week, mental stress, sleep duration, frequency of vigorous and moderate physical activities, and muscular strength exercises during the week. For boys, the odds ratio (OR) (95% confidence interval [CI]) between overweight and drug use were 0.990 (0.723–1.356; p = 0.950) for almost none, 0.939 (0.521–1.693; p = 0.834) for past use, and 0.791 (0.385–1.624; p = 0.523) for present use. The OR (95% CI) between obesity and drug use was 0.731(0.508–1.052; p = 0.091) for almost none, 0.755 (0.389–1.465; p = 0.407) for past use, and 0.701 (0.314–1.565; p = 0.386) for present use. For girls, the OR (95% CI) between overweight and drug use was 1.112 (0.702–1.763; p = 0.650) for almost none, 1.103 (0.464–2.619; p = 0.825) for past use, and 0.927 (0.267–3.218; p = 0.905) for present use. The OR (95% CI) between obesity and drug abuse was 0.594 (0.261–1.352; p = 0.215) for almost none, 1.318 (0.462–3.764; p = 606) for past use, and <0.001(<0.001–<0.001; p = 0.998) for present use. We concluded that recreational drug use had no correlation with overweight and obesity in Korean adolescents.     

Survival advantage from imatinib compared with the combination interferon-alpha plus cytarabine in chronic-phase chronic myelogenous leukemia: historical comparison between two phase 3 trials

In the multinational IRIS study comparing imatinib with interferon plus cytarabine (IFN/Ara-C) in patients with newly diagnosed chronic-phase chronic myelogenous leukemia (CP CML), imatinib demonstrated significantly higher rates of complete cytogenetic responses (CCyRs) and improved progression-free survival (PFS). However, because of a high early crossover rate to imatinib, survival benefit was not assessable. Here, we report the result of a study comparing long-term outcome of patients included in 2 prospective randomized trials: 551 patients assigned to imatinib in the IRIS trial from 2000 to 2001 and 325 patients who received the combination IFN/Ara-C in the CML91 trial between 1991 and 1996 before imatinib was available. With a follow-up of 42 months for both groups of patients, estimated CCyR, survival free of transformation, and overall survival were significantly higher with imatinib compared with IFN/Ara-C (P < .001, P = .004, and P < .001, respectively). Improved overall survival was also confirmed within different Sokal prognostic risk groups. Of interest, among all patients who achieved major cytogenetic response or CCyR at 12 months, the survival rate was similar irrespective of their treatment. In conclusion, within the limitation of this historical comparison, there is a survival advantage from first-line therapy with imatinib over IFN/Ara-C.     

Bone marrow transplantation for constitutional pure red cell aplasia

Constitutional pure red cell aplasia (CPRCA) is a syndrome of failed erythropoiesis usually diagnosed within the first year of life. Four patients with CPRCA received transplants with marrow from their HLA- identical, mixed lymphocyte culture-nonreactive siblings. All patients were resistant to corticosteroid therapy and were dependent on regular red cell transfusions for at least 5 years. Three patients were conditioned with procarbazine, antithymocyte globulin, cyclophosphamide, and busulfan, and one was conditioned with antithymocyte serum, cyclophosphamide, and busulfan. Three patients promptly had successful engraftments with establishment of donor hematopoiesis. One patient initially rejected his graft but received a successful retransplant. All patients are currently alive with Karnofsky performance scores of 100 and normal erythropoiesis of donor origin. Despite a history of multiple transfusions, bone marrow transplantation is a potentially curative therapy for patients with CPRCA.