No abstract

BackgroundViral infection is one of the risk factors for asthma exacerbation. However, which pathogens are related to asthma exacerbation in adults remains unclear.ObjectiveThe relation between various infections and adult asthma exacerbations was investigated in clinical practice.MethodsThe study subjects included 50 adult inpatients due to asthma exacerbations and 20 stable outpatients for comparison. The pathogens from a nasopharyngeal swab were measured by multiplex PCR analysis.ResultsAsthma exacerbations occurred after a common cold in 48 inpatients. The numbers of patients with viral, bacterial, or both infections were 16, 9, and 9, respectively. The dominant viruses were rhinoviruses, respiratory syncytial virus, influenza virus, and metapneumovirus. The major bacteria were S. pneumoniae and H. influenzae. Compared to pathogen-free patients, the patients with pathogens were older and non-atopic and had later onset of disease, lower FeNO levels, lower IgE titers, and a higher incidence of comorbid sinusitis, COPD, or pneumonia. Compared to stable outpatients, asthma exacerbation inpatients had a higher incidence of smoking and comorbid sinusitis, COPD, or pneumonia. Viruses were detected in 50% of stable outpatients, but a higher incidence of rhinovirus, respiratory syncytial virus, and metapneumovirus infections was observed in asthma exacerbation inpatients. H. influenzae was observed in stable asthmatic patients. Other bacteria, especially S. pneumoniae, were important in asthma exacerbation inpatients.ConclusionViral or bacterial infections were observed in 70% of inpatients with an asthma exacerbation in clinical practice. Infection with S. pneumoniae was related to adult asthma exacerbation.

We demonstrate the bistable lasing in a photonic molecule consisting of twin microdisks. When the photonic molecule was nonuniformly photopumped, the bistability and/or mode switching were observed with an effective pump power of <100μW. The rate equation analysis indicated that the operation was based on saturable absorption and gain switching, which depended on the nonuniformity, disk diameter detuning, and Q factors of coupled modes. Such a bistable laser, particularly showing the mode switching, will be applied for ultrasmall high-speed optical memories, flip-flops, and so on.

We demonstrate coupled-mode characteristics and bistability in photonic molecule lasers composed of evanescentcoupled GaInAsP twin microdisks. First, we show roomtemperature continuous-wave operation by photopumping and discuss the unique behavior of coupled modes, i.e., the anticrossing and splitting characteristics of bonding and antibonding modes. Next, we present the clear bistability, which is observed for the antibonding mode by nonuniform pumping with an effective power of nearly 40 µW. It is explained by rate equation analysis, which assumes saturable absorption. The analysis also predicts mode switching by the carrier-induced refractive index change. A micron-sized device with a very low power consumption will allow large scale integration of optical memories, optical flip-flops, and so forth.

No abstract