The need for large scale energy storage has become a priority to integrate renewable energy sources into the electricity grid. Redox flow batteries are considered the best option to store electricity from medium to large scale applications. However, the current high cost of redox flow batteries impedes the wide spread adoption of this technology. The membrane is a critical component of redox flow batteries as it determines the performance as well as the economic viability of the batteries. The membrane acts as a separator to prevent cross-mixing of the positive and negative electrolytes, while still allowing the transport of ions to complete the circuit during the passage of current. An ideal membrane should have high ionic conductivity, low water intake and excellent chemical and thermal stability as well as good ionic exchange capacity. Developing a low cost, chemically stable membrane for redox flow cell batteries has been a major focus for many groups around the world in recent years. This paper reviews the research work on membranes for redox flow batteries, in particular for the all-vanadium redox flow battery which has received the most attention.

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A case of post-transplantation pneumonia due to Candida krusei is reported. A 42-year-old man was admitted 28 days after heart transplantation with cough, pleuritic pain and fever. A chest computed tomograph showed multiple alveolar infiltrates bilaterally. He received broad-spectrum antibiotics, fluconazole for oral candidiasis, and cotrimoxazole for possible Pneumocystis carinii. A short-lived period of improvement was followed by respiratory failure. Cultures of bronchial washings grew C. krusei and C. albicans. The infection was documented by histology and culture obtained by transthoracic aspiration. Treatment with amphotericin B was initiated, but the patient died. Histology and culture of a pulmonary specimen, obtained immediately post mortem, further documented the infection with C. krusei.

Background Inflammatory bowel disease (IBD) is an independent risk factor for Clostridium difficile infection (CDI), which is associated significantly with disease severity. We aimed to determine the rates of CDI among hospitalized IBD patients in major tertiary referral hospitals in Greece. Patients and methods A retrospective analysis was carried out of stool cultures from hospitalized patients investigated for diarrhea, during 2016, tested for CDI with glutamate dehydrogenase (GDH) and toxins A and B. Results In total, 6932 patients were tested for CDI; 894 were positive for GDH (12.89%) and 339 were also positive for C. difficile toxin (4.89%). The prevalence of CDI among all hospitalized patients was 1.6/1000 patient-days. Among these, there were 401 IBD patients, and 62 were positive for GDH (15.46%) and 30 were also positive for C. difficile toxin (7.48%). The prevalence of CDI in IBD patients was 2.5/1000 patient-days, significantly higher than in non-IBD hospitalized patients (30/401 vs. 309/6531, P=0.013). Among the 30 IBD patients (ulcerative colitis=18, Crohn’s disease=12) with CDI, six were receiving biologics, three were on corticosteroids [one combined with azathioprine (AZA) and one combined with 5-ASA], nine were on AZA monotherapy and 12 were on 5-ASA monotherapy. The prevalence of CDI among patients receiving AZA monotherapy was significantly higher than in patients receiving other medications (9/68 vs. 21/333, P=0.047). Mild CDI (n=28) was treated with metronidazole and/or vancomycin, whereas severe CDI (n=2) was treated with vancomycin. Conclusion The prevalence of CDI is higher in hospitalized IBD patients than those without IBD and AZA monotherapy increases the risk of CDI.