METHODS: Gaussian effort model (GEM) is a derivative of the single-compartment model with basis function. GEM model uses a linear combination of basis functions to model the nonlinear pressure waveform of spontaneous breathing patients. The GEM model estimates respiratory mechanics such as Elastance and Resistance along with the magnitudes of basis functions, which accounts for patient inspiratory effort.
RESULTS AND DISCUSSION: The GEM model was tested using both simulated data and a retrospective observational clinical trial patient data. GEM model fitting to the original airway pressure waveform is better than any existing models when reverse triggering asynchrony is present. The fitting error of GEM model was less than 10% for both simulated data and clinical trial patient data.
CONCLUSION: GEM can capture the respiratory mechanics in the presence of patient effect in volume control ventilation mode and also can be used to assess patient-ventilator interaction. This model determines basis functions magnitudes, which can be used to simulate any waveform of patient effort pressure for future studies. The estimation of parameter identification GEM model can further be improved by constraining the parameters within a physiologically plausible range during least-square nonlinear regression.
METHODS: The kedondong powder was dried using five methods: convection oven drying, vacuum drying, spray drying, drum drying and freeze drying. The physical properties, flowability and DPPH radical scavenging ability of dried kedondong powder were examined.
RESULTS: Spray-dried powder provided the significantly (p ≤ 0.05) highest process yield, which was 54.93%. All the powder produced had a low moisture content (3.03 to 5.66%) and water activity (0.19–0.37). Visually, whitish and fine powders were observed on spray-dried and freeze-dried samples, while convection oven-dried and vacuum-dried powder appeared yellowish and coarse. The pH of the reconstituted powders varied from 2.71 to 2.83, where drum-dried powder was the most acidic. Spray-dried powder showed the highest wettability and shortest dissolution time, which was 172.65 s and 10.55 s, respectively. With the exception of drum-dried powder, all the dried powders were classified as non-caking powders. The bulk and tapped density of the powders ranged from 0.32 to 0.70 g/mL and 0.38 to 0.86 g/mL, respectively. Vacuum-dried powder had very good flowability, convection oven-dried and drum-dried powder had good flowability, while spray-dried and drum-dried powder had fair flowability. Antioxidant assay showed that freeze-dried powder exhibited the highest free radical scavenging activity (IC50 = 701.29 μg/mL).
CONCLUSIONS: This study indicates that spray-dried kedondong powder has great potential in the food industry due to its high process yield and better powder quality. Meanwhile, freeze drying best preserved the antioxidant properties of the powder, which could potentially be used as a functional ingredient as a result. This study is important for the fruit processing industry as it offers an alternative for the farmer to produce kedondong fruit powder because the fruit has a short shelf life. Converting the fruit into powder can diversify the resulting produce into different applications, such as fruit juice, beverages, jam and other food products.