COVID-19 outbreak and sectoral performance of the Australian stock market: An event study analysis.

The outbreak of COVID-19 has weakened the economy of Australia and its capital market since early 2020. The overall stock market has declined. However, some sectors become highly vulnerable while others continue to perform well even in the crisis period. Given this new reality, we seek to investigate the initial volatility and the sectoral return. In this study, we analyse data for eight sectors such as, transportation, pharmaceuticals, healthcare, energy, food, real estate, telecommunications and technology of the Australian stock market. In doing so, we obtain data from Australian Securities Exchange (ASX) and analysed them based on 'Event Study' method. Here, we use the 10-days window for the event of official announcement of the COVID-19 outbreak in Australia on 27 February 2020. The findings of the study show that on the day of announcement, the indices for food, pharmaceuticals and healthcare exhibit impressive positive returns. Following the announcement, the telecommunications, pharmaceuticals and healthcare sectors exhibit good performance, while poor performance is demonstrated by the transportation industry. The findings are vital for investors, market participants, companies, private and public policymakers and governments to develop recovery action plans for vulnerable sectors and enable investors to regain their confidence to make better investment decisions.

Preparation and evaluation of a non-viral gene vector for SiRNA: Multifunctional envelope-type nano device (.).

We prepared and evaluated a multifunctional envelope-type nano device (MEND) as a liver-targeting and long-circulation carrier for SiRNA. The polymer GA-PEG-Pp-DOPE was synthesized by modifying polyethylene glycol (PEG) with glycyrrhetinic acid (GA), peptide (Pp), and dioleoyl phosphoethanolamine (DOPE). The Pp is a substrate of matrix metalloproteinase 2. MEND was prepared with GA-PEG-Pp-DOPE and cationic phospholipids by the filming-rehydration method, and the orthogonal test was applied to optimize the prescription. The results of the biological evaluation results suggest that MEND is a promising delivery system for SiRNA.

Preparation and evaluation of multifunctional envelope-type nano device loading siRNA.

We prepared multifunctional envelope-type nano device (MEND) loading siRNA through lipid film hydration method; the qualities of MEND were characterized by the shape, particle size, and evaluated by the encapsulation efficiency (EE), plasma stability, and transfection efficiency. The formulated MEND was found to be relatively uniform in size with a positive zeta potential. The average siRNA entrapment efficiency was 86.4%. After 48 h exposure in 50% (v/v) serum at 37°C, the siRNA in MEND had no significant degradation. When the concentration of siRNA in 24-well plates was 500 nM, the MEND had high transfection efficiency, almost 100%.

Preparation and evaluation of liver-targeting micelles loaded with oxaliplatin.

We prepared liver-targeting micelles loaded with oxaliplatin (OXA), using a polymer modified by a liver-targeting ligand, namely, glycyrrhetinic acid-conjugated and stearic acid-grafted chitosan (GA-CS-SA). The particles had a uniform size, which was 138.6 ± 0.72 nm. The encapsulation efficiency was up to 71.7 ± 0.46%. The hepatic distribution of OXA in mice given OXA-GA-CS-SA was significantly superior to that in the controls (P < 0.05), which means that liver-targeted delivery of OXA was achieved. These results reveal that OXA-GA-CS-SA could be a potential and promising candidate for efficiently targeted delivery of OXA.

Preparation and characterization of glycyrrhetinic acid-modified stearic acid-grafted chitosan micelles.

Stearic acid-grafted chitosan (CS-SA) and glycyrrhetinic acid-conjugated stearic acid-grafted chitosan (GA-CS-SA) were synthesized and were further used for the preparation of micelles. The substitution degree (SD) of SA and GA on CS was measured. The physicochemical properties of CS-SA and GA-CS-SA micelles such as critical micelle concentration (CMC), aggregation number of hydrophobic micro-domain (AN), particle size, zeta potential, and morphology were also determined. The CMC of GA-CS-SA was about 17.49 µg/mL, which was relatively low. Its AN was 2.09. The GA-CS-SA micelles showed spherical shape with mean diameter of 121.1 nm and had positive charge, which suggested that GA-CS-SA could be a good carrier of cancer drug.

Preliminary pharmacokinetics of PEGylated oxaliplatin polylactic acid nanoparticles in rabbits and tumor-bearing mice.

To testify the targeting effect of PEGylated Oxaliplatin polylactic acid (OP-PEG-PLA) nanoparticles (NPs), we studied drug concentration in rabbit plasma and tissue distribution in tumor-bearing mice. Concentration of nanoparticle colloidal solution was performed with dialysis. Qualities of enriched NPs were characterized by particle size and drug content. OP concentration in samples was detected using ICP-MS. Compared to OP solution groups, OP concentration of NPs groups increased in the tumor (p < 0.05) and decreased in the kidney and heart (p < 0.05). Compared to OP-PLA NPs groups, OP concentration of OP-PEG-PLA NPs groups increased in the tumor and decreased in the liver and lung (p < 0.05). The concentrated OP-PEG-PLA NPs are good in clinical application and tumor delivery.

Preparation and evaluations in vitro of oxaliplatin polylactic acid nanoparticles.

The oxaliplatin nanoparticles were prepared with polylactic acid matrix, orthogonal test was applied to optimize the prescriptions, and the qualities of oxaliplatin nanoparticles were characterized by the shape, particle size, encapsulation efficiency (EE), and drug loading (DL). Oxaliplatin nanoparticle was prepared by solution replacement method. The formation of 0.25% Tween80, DMF-water 1:8 (v/v), oxaliplatin-polylactic acid 1:5 (w/w), and 20 mg/ml polylactic acid showed the suitable EE (17.4 ± 0.47%), DL (3.52 ± 0.07%). We observed the shape of oxaliplatin nanoparticles through SEM. The average size of the particles was 120.5 ± 8.7 nm, which was detected by N5 submicron particle size analyzer.