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Objective To identify the variables of videofluoroscopic swallowing study (VFSS) that are useful for predicting the risk of aspiration pneumonia in elderly patients with dysphagia.Methods A total of 251 patients (aged 65 years or more) were included and divided into a pneumonia group (n=133) and a non-pneumonia group (n=118). The pneumonia group included patients who had been diagnosed with aspiration pneumonia, and individuals in the non-pneumonia group did not have pneumonia but were referred for VFSS. The medical records and results of VFSS were reviewed and compared between the groups retrospectively.Results The pneumonia group exhibited a male preponderance and a higher 8-point Penetration-Aspiration Scale (8PPAS) score. The mean values of 8PPAS score for swallowing thick liquid and rice porridge was significantly higher in the pneumonia group. The pharyngeal delay time (PDT) and pharyngeal transit time (PTT) were significantly longer in the pneumonia group. The amounts of vallecular and pyriform sinus residue were increased in the pneumonia group. The delay in swallowing reflex and the decrease in laryngeal elevation were more frequently observed in the pneumonia group. Among those variables, PDT and PTT were identified as significant predictors of aspiration pneumonia based on logistic regression analysis.Conclusion The present study delineated the findings of VFSS, suggesting an increased risk of aspiration pneumonia in elderly patients with dysphagia. The results demonstrate that prolonged PDT and PTT are significant predictors of aspiration pneumonia.

Additional file 1. Materials and methods.

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Biologists are attempting to group genes based on the temporal pattern of gene expression levels. So far, a number of methods have been proposed for clustering microarray data. However, the results of clustering depends on the genes selection, therefore the gene selection with significant expression difference is also very important to cluster for microarray data. Thus, this paper present the results of broad comparative studies to time course microarray data by considering methods of gene selection, clustering and cluster validation.

Heat pump system can save energy and installation cost and reduces CO2 emissions. In this study, a system identification of an air source heat pump system using R410A with a variable speed compressor was experimentally investigated under various ambient and indoor temperature and cooling or heating capacity. The experimental study was also performed under cold and hot climate conditions as well as normal ambient temperature in cooling and heating mode. A heat pump system was installed and tested in an environment chamber, where temperature and humidity are precisely controlled. Experimental points were selected under 28 conditions for each cooling and heating mode using center composition design method. Developed steady-state model predicted the experimental values within 10% error. In this study, we carried out in-situ performance test of the air source heat pump system. Further study will be carried out for fault detection and diagnosis for a heat pump system using developed system identification model.