The objective of this investigation was to verify the hypothesis that the presence of lower airway bacterial colonization (LABC) can be a stimulating factor of airway inflammation, more frequent exacerbation, and impact on pulmonary function, independent of current tobacco smoking in the stable phase of chronic obstructive pulmonary disease (COPD). A total of 46 ex-smokers with moderate to severe COPD, 19 healthy non-smokers, and 17 ex-smokers without COPD were included in this study. Their sputum specimens were collected at the first baseline visit and at the second visit after a follow-up of one year. The samples were analyzed for bacterial growth by culture, and the levels of interleukin (IL)-6, IL-8, and tumor necrosis factor alpha (TNF-α) were measured by enzyme-linked immunosorbent assay (ELISA). The frequencies of exacerbations and pulmonary function were compared at visit 2. At visit 1, 37.0% (17/46) were found to have LABC with bacterial loads ≥10⁶ CFU/ml in their sputum specimens. Haemophilus influenzae was the predominant pathogenic organism isolated. IL-8, IL-6, and TNF-α in these patients' sputum were significantly higher than those without LABC (p < 0.05). It was the presence of LABC that contributed to the significantly elevated IL-8 and IL-6 at the 1-year period (p < 0.05). LABC was also associated with significantly increased frequencies of exacerbations and declined forced expiratory volume in 1 s (FEV₁) (p < 0.05). LABC was documented in a subpopulation of stable COPD patients; it may be responsible for the deterioration of pulmonary function of COPD patients by promoting airway inflammation and/or increased frequency of exacerbations independently of tobacco smoking.

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The back-streaming neutrons (Back-n) facility at China Spallation Neutron Source (CSNS) provides an excellent white neutron source for accurate nuclear data measurements. At Back-n, the GAmma spectrometer with GErmanium Array (GAEA) in planning is designed to measure neutron-induced cross-sections, nuclear structure, and in-beam nuclear spectroscopy. As GAEA consists of various detectors, developing and maintaining the readout electronics for this spectrometer is challenging. A prototype of readout electronics based on the universal digital readout platform is proposed in this paper. The digitizer in the platform consists of a data processing carrier and a signal acquire mezzanine. Different mezzanines are designed to accommodate various detectors in GAEA. The carrier's firmware also has a universal part for data readout and a reconfigurable module for real-time data processing. In order to synchronize all digitizers, a time synchronization module is designed, based upon which a global synchronous network is constructed with PXIe chassis. Critical signals as the clock, trigger, and control can be synchronously distributed over this network with high precision, significantly simplifying the whole readout electronics. Several tests were carried out to evaluate the prototype. The measured FWHM of the 22Na characteristic peak at 1274.5 keV is better than 0.15% for the HPGe detector. The measured time resolution of the readout electronics is 34.7 ps. Test results show that the performance of the readout electronics can meet GAEA requirements.

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