[Impacts of COVID-19 Lockdown on Air Quality in Shenzhen in Spring 2022].

The short-term reduction of air pollutant emissions is an important emergency control measure for avoiding air pollution exceedances in Chinese cities. However, the impacts of short-term emission reductions on the air qualities in southern Chinese cities in spring has not been fully explored. We analyzed the changes in air quality in Shenzhen, Guangdong before, during, and after a city-wide lockdown associated with COVID-19 control during March 14 to 20, 2022. Stable weather conditions prevailed before and during the lockdown, such that local air pollution was strongly affected by local emissions. In-situ measurements and WRF-GC simulations over the Pearl River Delta (PRD) both showed that, due to reductions in traffic emissions during the lockdown, the concentrations of nitrogen dioxide (NO2), respirable particulate matter (PM10), and fine particulate matters (PM2.5) in Shenzhen decreased by (-26±9.5)%, (-28±6.4)%, and (-20±8.2)%, respectively. However, surface ozone (O3) concentration did not change significantly[(-1.0±6.5)%]. TROPOMI satellite observations of formaldehyde and nitrogen dioxide column concentrations indicated that the ozone photochemistry in the PRD in spring 2022 was mainly controlled by the volatile organic compound (VOCs) concentrations and was not sensitive to the reduction in nitrogen oxide (NOx) concentrations. Reduction in NOx may even have increased O3, because the titration of O3 by NOx was weakened. Due to the small spatial-temporal extent of emission reductions, the air quality effects caused by this short-term urban-scale lockdown were weaker than the air quality effects across China during the widespread COVID-19 lockdown in 2020. Future air quality management in South China cities should consider the impacts of NOx emission reduction on ozone and focus on the co-reduction scenarios of NOx and VOCs.

Analysis of Factors Influencing Air Quality in Different Periods during COVID-19: A Case Study of Tangshan, China.

This study aimed to analyze the main factors influencing air quality in Tangshan during COVID-19, covering three different periods: the COVID-19 period, the Level I response period, and the Spring Festival period. Comparative analysis and the difference-in-differences (DID) method were used to explore differences in air quality between different stages of the epidemic and different years. During the COVID-19 period, the air quality index (AQI) and the concentrations of six conventional air pollutants (PM2.5, PM10, SO2, NO2, CO, and O3-8h) decreased significantly compared to 2017-2019. For the Level I response period, the reduction in AQI caused by COVID-19 control measures were 29.07%, 31.43%, and 20.04% in February, March, and April of 2020, respectively. During the Spring Festival, the concentrations of the six pollutants were significantly higher than those in 2019 and 2021, which may be related to heavy pollution events caused by unfavorable meteorological conditions and regional transport. As for the further improvement in air quality, it is necessary to take strict measures to prevent and control air pollution while paying attention to meteorological factors.

Multiple branch retinal artery occlusions following the new facial cosmetic filler (Poly-D, L-lactic Acid) injection a case report.

BACKGROUND: Poly-D, L-lactic acid is (PDLLA) a new cosmetic filler. We reported the first case of PDLLA-related devastating complication of multiple branch retinal artery occlusion (BRAO). CASE PRESENTATION: A 23-year-old female had sudden blindness after injection of PDLLA at the glabella. After emergency intraocular pressure-lowering medicine, ocular massage, steroid pulse therapy, heparin and alprostadil infusion, and subsequent treatments including acupuncture and 40 sessions of hyperbaric oxygen therapy, her best-corrected visual acuity improved from hand motion at 30 cm to 0.3 within 2 months. CONCLUSION: Although safety of PDLLA was evaluated in animal studies and in 16,000 human cases, it could still cause rare but devastating retinal artery occlusion as in the present case. Proper and immediate therapies could still improve patient's vision and scotoma. Surgeons should keep in mind the possibility of iatrogenic filler-related retinal artery occlusion.

Protein sensors combining both on-and-off model for antibody homogeneous assay.

Protein sensors based on allosteric enzymes responding to target binding with rapid changes in enzymatic activity are potential tools for homogeneous assays. However, a high signal-to-noise ratio (S/N) is difficult to achieve in their construction. A high S/N is critical to discriminate signals from the background, a phenomenon that might largely vary among serum samples from different individuals. Herein, based on the modularized luciferase NanoLuc, we designed a novel biosensor called NanoSwitch. This sensor allows direct detection of antibodies in 1 µl serum in 45 min without washing steps. In the detection of Flag and HA antibodies, NanoSwitches respond to antibodies with S/N ratios of 33-fold and 42-fold, respectively. Further, we constructed a NanoSwitch for detecting SARS-CoV-2-specific antibodies, which showed over 200-fold S/N in serum samples. High S/N was achieved by a new working model, combining the turn-off of the sensor with human serum albumin and turn-on with a specific antibody. Also, we constructed NanoSwitches for detecting antibodies against the core protein of hepatitis C virus (HCV) and gp41 of the human immunodeficiency virus (HIV). Interestingly, these sensors demonstrated a high S/N and good performance in the assays of clinical samples; this was partly attributed to the combination of off-and-on models. In summary, we provide a novel type of protein sensor and a working model that potentially guides new sensor design with better performance.

Knowledge, Attitude, and Awareness of Health Insurance in Travel during the Covid-19 Pandemics (preprint)

Background Travel has become one of the most popular leisure activities in the world, especially international traveling. The risk of accident and travel related illness including infectious and non-communicable diseases should not be neglected. To provide more comprehensive pre-travel consultation to the international travelers, we aimed to investigate the knowledge, attitude, and awareness of travel health insurance for travelers.Methods Anonymous structured questionnaires were distributed to 1,000 visitors of the Taiwan International Travel Fair in May 2019.Results The top three kinds of travel health insurance were accidental death and disablement insurance (92%), accidental medical reimbursement (90.4%) and 24 hours of emergency assistance (89%). In addition to education level, travel-associated illness, and special activities during travel, a significant association was observed between the willingness to buy various travel insurance and willingness of pre-travel consultation.Conclusions Although most travelers would buy travel health insurance, disproportional respondents understood the content of travel insurance. Most travelers considered travel clinics to be the most reliable information resources of travel insurance. Therefore, travel specialists are encouraged to offer more information about travel insurance during pre-travel consultation, especially during the COVID-19 pandemic.

Clinical Features of 69 Cases With Coronavirus Disease 2019 in Wuhan, China.

BACKGROUND: From December 2019 to February 2020, 2019 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a serious outbreak of coronavirus disease 2019 (COVID-19) in Wuhan, China. Related clinical features are needed. METHODS: We reviewed 69 patients who were hospitalized in Union hospital in Wuhan between 16 January and 29 January 2020. All patients were confirmed to be infected with SARS-CoV-2, and the final date of follow-up was 4 February 2020. RESULTS: The median age of 69 enrolled patients was 42.0 years (interquartile range 35.0-62.0), and 32 patients (46%) were men. The most common symptoms were fever (60 [87%]), cough (38 [55%]), and fatigue (29 [42%]). Most patients received antiviral therapy (66 [98.5%] of 67 patients) and antibiotic therapy (66 [98.5%] of 67 patients). As of 4 February 2020, 18 (26.9%) of 67 patients had been discharged, and 5 patients had died, with a mortality rate of 7.5%. According to the lowest SpO2 during admission, cases were divided into the SpO2 ≥ 90% group (n = 55) and the SpO2 < 90% group (n = 14). All 5 deaths occurred in the SpO2 < 90% group. Compared with SpO2 ≥ 90% group, patients of the SpO2 < 90% group were older and showed more comorbidities and higher plasma levels of interleukin (IL) 6, IL10, lactate dehydrogenase, and C reactive protein. Arbidol treatment showed tendency to improve the discharging rate and decrease the mortality rate. CONCLUSIONS: COVID-19 appears to show frequent fever, dry cough, and increase of inflammatory cytokines, and induced a mortality rate of 7.5%. Older patients or those with underlying comorbidities are at higher risk of death.

SARS-CoV-2 RNA reference materials

Coronavirus disease (COVID-19) is an acute infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Reverse transcription real-time fluorescent quantitative polymerase chain reaction (RT-qPCR) was the firstly authorized method for the detection of SARS-CoV-2 RNA. As this method is sensitive, specific, it has been widely recognized as the golden standard for the diagnosis of COVID-19. Unfortunately, several false-negative cases have been reported after the outbreak of COVID-19, probably due to the quality of the kits or the improper operation of RT-qPCR. Nucleic acid reference materials (RM) are the key element for the metrology traceability and quality control of SARS-CoV-2 RNA detection, but the development of RNA RM remains a challenge in the biology metrology field. Two main problems are the low stability of the RNA sample and the lack of proven absolute quantification methods. To establish the measurement traceability for SARS-CoV-2 RNA detection, a novel RNA reference material (RM) was developed. The RM is a mixed solution of 3 in vitro transcribed RNA molecules which cover different key target sequences of SARS-CoV-2 gene: The full-length of nucleoprotein (N) gene (28274-29533, GenBank: MT027064.1), the full-length of envelope protein (E) gene (26245-26472, GenBank: MT027064.1), and partial sequence of open reading frame 1ab (ORF1ab) (13321-15540, GenBank: MT027064.1). The purity of the transcribed RNA molecules was verified by a biological analyzer. The results showed that the molecular length of all the RNA molecules were consistent with our design. The clear peaks of our RNA RMs strongly demonstrated good purity. For absolute quantification of RNA RMs, we studied digital PCR (dPCR) for RNA samples. Digital PCR evenly partitioned the sample and PCR reaction solution to a very large number of units, on a microporous chip or in the liquid droplets, etc. After a PCR amplification reaction, the fluorescence signal was detected for each unit individually, with a binary readout of "0" or "1" for negative and positive results respectively. Through the statistics of positive results based on the Poisson distribution, the copy number of RNA sample was accurately determined without standard curves needed. Digital PCR has significantly higher reliability and accuracy. Mainly based on the PCR primers and probes for SARS-CoV-2 detection suggested by the Chinese CDC and WHO, we optimized the key factors of dPCR towards improved amplification efficiency. Through digital PCR measurements by 4 laboratories, the certified values of concentration (copies/mu L) were assigned for the N gene, E gene, and ORF1ab gene in the mixed RM. Single-stranded RNA is unstable and easy to be degraded by RNase in the environment, thus the optimization of RNA protectants is very important for the stability of RNA RMs. During the study of the stability, we found that a proper protector (1 mmol/L DTT and 0.5 U/L Rnase Inhibitor) can effectively increase the valid storage life of our RNA RM. Based on the latest data, the concentration of our RNA RMs was stable for at least 30 d under -80 degrees C storage and 13 d under -4 degrees C storage. In order to verify the applicability of our RNA RM in the actual virus detection process, we analyzed our RMs using 9 SARS-CoV-2 nucleic acid detection kits. These virus RNA detection kits were from different manufacturers with various detection principles, that are being applied in laboratories for virus detection. Finally, our RNA RMs showed high generalizability among 9 kits. The development of RNA RM provides the metrological basis for the quality control of SARS-CoV-2 detection kits.