Multidimensional Frailty Instruments Can Predict Acute Exacerbations Within One Year in Patients with Stable Chronic Obstructive Pulmonary Disease: A Retrospective Longitudinal Study.

Background: Chronic obstructive pulmonary disease (COPD) is closely associated with frailty, and prevention of acute exacerbations is important for disease management. Moreover, COPD patients with frailty experience a higher risk of acute exacerbations. However, the frailty instruments that can better predict acute exacerbations remain unclear. Purpose: (1) To explore the factors influencing frailty and acute exacerbations in stable COPD patients, and (2) quantify the ability of multidimensional frailty instruments to predict acute exacerbations within 1 year. Patients and methods: In this retrospective longitudinal study, stable COPD patients were recruited from the outpatient department of Sichuan Provincial People's Hospital from July 2022 to June 2023. COPD patients reviewed their frailty one year ago and their acute exacerbations within one year using face-to-face interviews with a self-developed frailty questionnaire. Frailty status was assessed using the Frailty Index (FI), frailty questionnaire (FRAIL), and Clinical Frailty Scale (CFS). One-way logistic regression was used to explore the factors influencing frailty and acute exacerbations. Multivariate logistic regression was used to establish a prediction model for acute exacerbations, and the accuracy of the three frailty instruments was compared by measuring the area under the receiver operating characteristic curve (AUC). Results: A total of 120 individuals were included. Frailty incidence estimates using FI, FRAIL, and CFS were 23.3%, 11.7%, and 15.8%, respectively. The three frailty instruments showed consistency in COPD assessments (P<0.05). After adjusting for covariates, frailty reflected by the FI and CFS score remained an independent risk factor for acute exacerbations. The CFS score was the best predictor of acute exacerbations (AUC, 0.764 (0.663-0.866); sensitivity, 57.9%; specificity, 80.0%). Moreover, the combination of CFS plus FRAIL scores was a better predictor of acute exacerbations (AUC, 0.792 (0.693-0.891); sensitivity, 86.3%; specificity, 60.0%). Conclusion: Multidimensional frailty assessments could improve the identification of COPD patients at high risk of acute exacerbations and facilitate targeted interventions to reduce acute exacerbations in these patients.

Ultra-Low-Density Carbon Nanotube Aerogel Film for Fast and Sensitive Bolometric Sensing.

In various applications, infrared (IR) detectors with quick responses and high sensitivity at room temperature are essential. This work synthesizes carbon nanotube aerogel films (CAFs) with an ultra-low density of 1.33 mg cm-3. Transient electrothermal (TET) technology is used to characterize the thermal and electrical transport of CAFs in the temperature range of 320 to 10 K. CAF has record-low thermal conductivity (2.5 mW m-1 K-1 at 320 K) and thermal diffusivity (2.24 × 10-6 m2 s-1 at 320 K) in vacuum. The TCR of CAF is -0.11%/K at 295 K, which is 57% higher than that of the MWCNT films. In addition, the comprehensive bolometric performance of carbon nanotube aerogels is tested and analyzed, including the photothermal response, resistivity responsivity, and response time to lasers of a broad spectrum from ultraviolet to near-infrared. The relative responsivity of CAF to lasers of different wavelengths is found to be consistent. The response time of CAF with 200 µm suspended length is measured to be as short as 2.95-3.03 ms (framing rate of 330-339 per second). In addition, the resistive response of the CAF sample to a blackbody radiator and the radiation of the human hand also shows good sensitivity and repeatability. These results demonstrate the promising application of CAF as a sensitive and fast-response uncooled bolometer.