Discomfort estimation for aircraft cabin noise using linear regression and modified psychoacoustic annoyance approaches.

Appropriate sound quality models for noise-induced discomfort are necessary for a better acoustic comfort design in the aircraft cabin. This study investigates the acoustic discomfort in two large passenger aeroplanes (i.e., planes A and B). We recorded the noise at 21 positions in each aircraft cabin and selected 42 stimuli ranging from 72 to 81 dB(A) during the cruising flights. Twenty-four participants rated the noise discomfort by the absolute magnitude estimation method. The discomfort values in the middle section of the aircraft cabin are 10% points higher than in the front or rear section. The discomfort magnitude was dominated by loudness and influenced by roughness and sharpness. A multiple linear (MA) discomfort model was established, accounting for the relationship between the discomfort and sound quality metrics (i.e., loudness, sharpness, and roughness). The MA model estimated noise discomfort better than the Zwicker and other (i.e., More and Di) psychoacoustic annoyance (PA) models. We modified the coefficients of independent variables in the formulations of Zwicker, Di, and More PA models, respectively, according to the present experimental results. The correlation coefficients between the estimated and measured values of the modified models were at least 20% points higher than the original ones.

A Liposomal Formulation for Improving Solubility and Oral Bioavailability of Nifedipine.

Proliposomes were used to improve the solubility and oral bioavailability of nifedipine. Nifedipine proliposomes were prepared by methanol injection-spray drying method. The response surface method was used to optimize formulation to enhance the encapsulation efficiency (EE%) of nifedipine. The particle size of nifedipine proliposomes after rehydration was 114 nm. Surface morphology of nifedipine proliposomes was observed by a scanning electron microscope (SEM) and interaction of formulation ingredients was assessed by differential scanning calorimetry (DSC). The solubility of nifedipine is improved 24.8 times after forming proliposomes. In vitro release experiment, nifedipine proliposomes had a control release effect, especially in simulated gastric fluid. In vivo, nifedipine proliposomes significantly improved the bioavailability of nifedipine. The area under the concentration-time curve (AUC0-∞) of nifedipine proliposomes was about 10 times than nifedipine after oral administration. The elimination half-life (T1/2ß) of nifedipine was increased from 1.6 h to 6.6 h. In conclusion, proliposomes was a promising system to deliver nifedipine through oral route and warranted further investigation.

Single-step microfluidic synthesis of transferrin-conjugated lipid nanoparticles for siRNA delivery.

Microfluidic systems can accelerate clinical translation of nanoparticles due to their ability to generate nanoparticles in a well-controlled and reproducible manner. In this study, a single-step process based on microfluidic focusing (MF) was employed to synthesize transferrin-conjugated lipid nanoparticles (Tf-LNPs) and the method was compared with a multi-steps bulk mixing (BM) method. The results indicate that this single-step MF process enables rapid and efficient synthesis of Tf-LNPs, which were named Tf-LNPs-MF. Tf-LNPs-MF was shown to have a smaller size and more uniform structures compared to LNPs produced by multi-steps BM method (Tf-LNPs-BM). Furthermore, efficient cellular uptake of Tf-LNPs-MF in vitro as well as greater tumor inhibition in vivo proved that Tf-LNPs-MF had higher siRNA delivery efficiency in vitro and in vivo. Taken together, this single-step microfluidic synthesis significantly simplified the Tf-LNPs production and improved their drug delivery properties and may serve as a valuable tool for developing new cancer therapies.