No abstract

The precise mechanism of performance degradation in polymer electrolyte membrane fuel cells (PEMFCs) under the fuel starvation condition is investigated by simultaneously monitoring the potential behavior and exhaust gas from the anode using the hydrogen reference electrode and in situ online mass spectrometry. Interestingly, the water electrolysis begins at a lower potential range, and carbon oxidation occurs at a higher range as the alternative reaction to hydrogen oxidation. Thus, carbon corrosion, which is detrimental to cell performance, can be reduced by extending the duration of the water electrolysis reaction. In this regard, the introductions of the graphitized carbon support and water electrolysis catalyst to anode are effective in alleviating the damage due to fuel starvation by rendering the dominant alternative reaction to continue the water electrolysis.

No abstract

Chronic cough is common in the community and causes significant morbidity. Several factors may underlie this problem, but comorbid conditions located at sensory nerve endings that regulate the cough reflex, including rhinitis, rhinosinusitis, asthma, eosinophilic bronchitis, and gastroesophageal reflux disease, are considered important. However, chronic cough is frequently non-specific and accompanied by not easily identifiable causes during the initial evaluation. Therefore, there are unmet needs for developing empirical treatment and practical diagnostic approaches that can be applied in primary clinics. Meanwhile, in referral clinics, a considerable proportion of adult patients with chronic cough are unexplained or refractory to conventional treatment. The present clinical practice guidelines aim to address major clinical questions regarding empirical treatment, practical diagnostic tools for non-specific chronic cough, and available therapeutic options for chronic wet cough in children and unexplained chronic cough in adults in Korea.

No abstract

PurposeIdentification of tolerable alternative analgesics is crucial for management in nonsteroidal anti-inflammatory drug (NSAID)-sensitive patients. We investigated cross-reactivity of acetaminophen and celecoxib according to the type of aspirin/NSAID hypersensitivity and aimed to determine the risk factors for cross-intolerance.MethodsWe retrospectively reviewed the medical records of patients intolerant to aspirin and NSAIDs who had undergone an acetaminophen and/or celecoxib oral provocation test. Aspirin/NSAID hypersensitivity was classified into 4 types according to a recently proposed classification: aspirin-exacerbated respiratory disease (AERD), aspirin-exacerbated chronic urticaria (AECU), aspirin-induced acute urticaria/angioedema (AIAU), and NSAID-induced blended reaction (NIRD).ResultsA total of 180 patients with hypersensitivity to aspirin and NSAIDs were enrolled; 149 acetaminophen provocation test results and 145 celecoxib provocation test results were analyzed. The overall cross-reaction rates to acetaminophen and celecoxib were 24.8% and 10.3%, respectively. There was a significant difference in the cross-reactivity to acetaminophen according to the type of NSAID hypersensitivity. Cross-reactivity to acetaminophen was highest in the AECU group (43.9%), followed by the AERD (33.3%), NIBR (16.7%), and AIAU (12.5%) groups. Underlying chronic urticaria was more prevalent in patients with cross-intolerance to both acetaminophen (P=0.001) and celecoxib (P=0.033). Intolerance to acetaminophen was associated with intolerance to celecoxib (P<0.001).ConclusionsAcetaminophen and celecoxib may induce adverse reactions in a non-negligible portion of aspirin/NSAID-sensitive patients. Physicians should be aware of the possible cross-reactions of these alternative drugs and consider an oral challenge test to confirm their tolerability.

Quaternized polymers as electrode ionomeric binders enable fuel cell operation under high-pH or anhydrous conditions. Herein we report quaternized poly­(fluorene) ionomers with controlled hydrophobicity (contact angle of electrodes with the ionomers 109–164°) by changing the length of tethered fluoroalkyl chains. The anion-exchange membrane fuel cell employing the hydrophobic ionomer exhibits improved durability (voltage loss 0.41 mV h–1) through better water management. The high-temperature proton-exchange-membrane fuel cell using the ionomer shows superior H2/air performance (1.7 A cm–2 at 0.4 V). The finding in this study highlights the benefits of hydrophobic ionomers for emerging fuel cell applications.

No abstract