Internet penetration and airline pricing: Evidence from China

This paper investigates the impacts of increasing Internet penetration on airfares and price dispersion in the Chinese airline market. It is found that an increase in Internet penetration is associated with higher average airfares and lower price dispersion between the major Chinese carriers. It appears that the increase in Internet penetration seems to have strengthened the major airlines’ ability to maintain price stability, which is an indication of the existence mutual forbearance among the major carriers confirmed in other studies. Higher prices and lower price dispersion are mostly to occur in the most heavily markets. This research also finds that if carriers possess similar degree of market power, the price dispersion between the airline pair is smaller. The findings can generate important policy insights, and inform anti-trust policies in the post-Covid period, when more consumers use Internet for search and inquiries, and when big data and artificial intelligence technologies mature.

Hydrophilic rhodamine B-loaded / boronic acid-modified graphene oxide nanocomposite as a substitute of enzyme-labeled second antibody for ultrasensitive detection of antibodies.

Enzyme-labeled secondary antibody is often used to amplify the output signal in the process of antibody detection. However, its preparation process is complex and time-consuming. Herein, we fabricated an innovative hydrophilic rhodamine B-loaded / boronic acid-modified graphene oxide (HRBGO) nanocomposite, used as a substitute of enzyme-labeled second antibody. The synthetic HRBGO was loaded with generous rhodamine B and modified with boronic acid. Therefore, the HRBGO could selectively label the carbohydrate chains of Fc fragment of primary antibody through specific boronate affinity recognition, and then perform signal output and amplification by releasing rhodamine B. To verify the practicability of HRBGO, trastuzumab as a humanized monoclonal antibody targeting human epidermal growth factor receptor-2 (HER2) was selected as model antibody. A glycosylation site-blocked / HER2-immobilized magnetic nanoparticles (GHMN) was also prepared for selectively capturing trastuzumab from complex samples via specific immunoaffinity. Because the glycosylation sites of HER2 can also be labeled with the HRBGO by boronate affinity recognition, these sites were blocked by a masking agent to minimize the background signal. For specific and ultrasensitive detection of trastuzumab, the integration of GHMN and HRBGO was proposed and optimized in detail. Trastuzumab detection based on HRBGO consisted of three steps: specific capture, selective labeling, and output signal. The proposed strategy provided ultrahigh sensitivity with limit of detection of 0.35 fg mL-1 and was successfully applied in the detection of trastuzumab in spiked serum sample with recovery and relative standard deviation in the range of 98.7-103.8% and 3.8-6.0%, respectively. To assess universal applicability, the HRBGO was also successfully used for the determination of anti-SARS-COV2 RBD antibody in human serum sample.

The cardiovascular disorders and prognostic cardiac biomarkers in COVID-19.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) leads to the outbreak of coronavirus disease 2019 (COVID-19), a worldwide epidemic disease affecting increasing number of patients. Although the virus primarily targets respiratory system, cardiovascular involvement has been reported in accumulating studies. In this review, we first describe the cardiac disorders in human with various types of CoV infection, and in animals infected with coronavirus. Particularly, we will focus on the association of cardiovascular disorders upon SARS-CoV-2 infection, and prognostic cardiac biomarkers in COVID-19. Besides, we will discuss the possible mechanisms underlying cardiac injury resulted from SARS-CoV-2 infection including direct myocardial injury caused by viral infection, reduced level of ACE2, and inflammatory response during infection. Improved understandings of cardiac disorders associated with COVID-19 might predict clinical outcome and provide insights into more rational treatment responses in clinical practice.