Numerical investigation of the impacts of environmental conditions and breathing rate on droplet transmission during dental service

Dental services are yet to return to a semblance of normality owing to the fear and uncertainty associated with the possible airborne transmission of diseases. The present study aims to investigate the impacts of environmental conditions [changes in ventilation location, ventilation rate, and relative humidity (RH)] and variations in dental patient's breathing rate on droplet transmission during dental service. Computational fluid dynamics simulation was performed based on our previous experimental study during ultrasonic scaling. The impacts of different factors were numerically analyzed by the final fate and proportion of emitted droplets in the dental surgery environment. The results revealed that about 85% of droplets deposited near the dental treatment region, where the patient's torso, face, and floor (dental chair) accounted for around 63%, 11%, and 8.5%, respectively. The change in the ventilation location had a small impact on the deposition of larger droplets (> 60 mu m), and a spatial region with high droplet mass concentration would be presented near the dental professional. The change in the ventilation rate from 5 to 8 ACH led to a 1.5% increment in the fraction of escaped droplets. 50% RH in dental environments was recommended to prevent droplets' fast evaporation and potential mold. Variations in the patient's breathing rate had little effect on the final fate and proportion of emitted droplets. Overall, environmental factors are suggested to maintain 50% RH and larger ACH in dental surgery environments. The findings can give policymakers insights into the role of environmental factors on infection control.

An approach combining bioinformatics and machine learning to identify eight autophagy-related biomarkers and construct molecular mechanisms underlying COVID-19 and major depressive disorders.

OBJECTIVE: A lack of objective biomarkers is preventing the screening and diagnosis of COVID-19 combined with major depression disorder (COVID-19-MDD). The purpose of this study was to identify diagnostic biomarkers and gene regulatory mechanisms associated with autophagy; a crucial process significantly involved in the pathogenesis of COVID-19-MDD. MATERIALS AND METHODS: In this study, differentially expressed genes (DEGs) were screened using GSE98793 from the GEO2R analysis (GEO) database, and intersected with the COVID-19-related gene (CRGs) and autophagy-related genes (ARGs) to obtain common genes involved in. Then, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of these common genes were performed. Subsequently, the transcription factor (TF)-gene regulatory network and comorbidity network were constructed. In addition, 10 drug candidates were screened using the DSigDB database. To identify diagnostic markers, we used LASSO regression. RESULTS: In total, 13 common genes were screened, which were primarily enriched in lysosomes, endoplasmic reticulum membranes, and other endomembrane systems also associated with autophagy. Additionally, these genes were involved in neurological cell signaling and have a functional role in pathways related to vascular endothelial growth factor, tyrosine kinase, autophagy, inflammation, immunity, and carcinogenesis. Tumors and psychiatric disorders were the most highly linked diseases to COVID-19. Finally, ten drug candidates and eight diagnostic markers (STX17, NRG1, RRAGD, XPO1, HERC1, HSP90AB1, EPHB2, and S1PR3) were screened. CONCLUSIONS: This is the first study to screen eight diagnostic markers and construct a gene regulatory network for COVID-19-MDD from the perspective of autophagy. The findings of our study provide novel insights into the diagnosis and treatment of COVID-19-MDD.

Airborne transmission during short-term events: Direct route over indirect route

Numerous short-term exposure events in public spaces were reported during the COVID-19 pandemic, especially during the spread of Delta and Omicron. However, the currently used exposure risk assessment models and mitigation measures are mostly based on the assumption of steady-state and complete-mixing conditions. The present study investigates the dynamics of airborne transmission in short-term events when a steady state is not reached before the end of the events. Large-eddy simulation (LES) is performed to predict the airborne transmission in short-term events, and three representative physical distances between two occupants are examined. Both time-averaged and phase-averaged exposure indices are used to evaluate the exposure risk. The results present that the exposure index in the short-term events constantly varies over time, especially within the first 1/ACH (air changes per hour) hour of exposure between occupants in close proximity, posing high uncertainty to the spatial and temporal evolutions of the risk of cross-infection. The decoupling analysis of the direct and indirect airborne transmission routes indicates that the direct airborne transmission is the predominated route in short-term events. It suggests also that the general dilution ventilation has a relatively limited efficiency in mitigating the risk of direct airborne transmission, but determines largely the occurrence time of the indirect one. Given the randomness, discreteness, localization, and high-risk characteristics of direct airborne transmission, a localized method that has a direct interference on the respiratory flows would be better than dilution ventilation for short-term events, in terms of both efficiency and cost.

A Six-degree-of-freedom Face Tracking Method for Non-contact Physiological Detection Robot

Due to the COVID-19 epidemic, there has been a high demand for non-contact diagnostic equipment that can reduce exposure and cross-infection. A non-contact medical detection robot is a type of diagnostic equipment and medical service robot with a wide application prospect. However, few non-contact medical detection robots have been designed to collect patients' physiological parameters when they are in inconvenient situations, such as bedridden, during clinical usage. A six-degree-of-freedom (six-DOF) face tracking method based on a six-DOF robot is proposed in this paper. In the proposed system, a face detector equipped with a camera attached to the robot's wrist is used to obtain the real-time face depth and attitude information. The optimal target attitude of the camera is calculated according to the constraints in the base coordinate system. A closed-loop controller is designed to control the robot to reach the target position and posture smoothly. The experiment with a six-DOF robot has verified that the proposed system can achieve the real-time tracking of human faces by a camera. The proposed method can also be used in many other scenarios where six-DOF face tracking is required by robots.

Analysis of the changes and characteristics of pediatric outpatient visits in a general hospital in Beijing before and after the COVID-19 pandemic

OBJECTIVE: To analyze the changes and characteristics of pediatric outpatient visits in a general hospital before and after the coronavirus disease (COVID-19) epidemic. METHODS: Based on the registration data of pediatric outpatient visits in the information system (HIS)of Beijing Tsinghua Changgung Hospital, from January 1 2018 to December 31 2020, aged 0 to 16 years, we analyzed the changes of outpatient visits before and after the epidemic, focusing on respiratory infection including influenza. The relationship between the outpatient visits and age and quarterly distribution were also studied. RESULTS: (1) Respiratory infection accounted for the majority of outpatient visits in 2018 and 2019 (60.6% and 60.5%, respectively). Non-respiratory infection accounted for the main proportion of outpatient visits in 2020, while respiratory infection accounted for only 47.4%. Annual respiratory infection visits, respiratory infectious diseases visits especially influenza visits all decreased significantly in 2020 compared with that in 2018 and 2019 (P < 0.05). (2)Respiratory infection visits were highest in the infant group, lowest in the school age group (P < 0.05) and highest in the fourth quarter each year. It decreased significantly in the second quarter of 2020 with statistical significance when compared with the other quarters of 2020(P < 0.05). (3)Influenza accounted for the highest proportion of respiratory infectious diseases visits in each year. It was highest in first quarter, which was significantly different from the other quarters of the year (P < 0.05). There were different distributions of influenza visits throughout 2018 and 2019, while it was only distributed in the first quarter and 99% in January in 2020. CONCLUSION: The respiratory infection and influenza visits have decreased significantly in our pediatric outpatient department after the COVID-19 epidemic, which is considered closely related to the lifestyle and personal protection after the epidemic. It is recommended that health education on respiratory infection and influenza prevention should be strengthened, especially in winter and spring, to promote the development of good respiratory and hand hygiene habits.

Epidemiological characteristics and spatial-temporal analysis of COVID-19 in Shandong Province, China.

The pandemic of coronavirus disease 2019 (COVID-19) has posed serious challenges. It is vitally important to further clarify the epidemiological characteristics of the COVID-19 outbreak for future study and prevention and control measures. Epidemiological characteristics and spatial-temporal analysis were performed based on COVID-19 cases from 21 January 2020 to 1 March 2020 in Shandong Province, and close contacts were traced to construct transmission chains. A total of 758 laboratory-confirmed cases were reported in Shandong. The sex ratio was 1.27: 1 (M: F) and the median age was 42 (interquartile range: 32-55). The high-risk clusters were identified in the central, eastern and southern regions of Shandong from 25 January 2020 to 10 February 2020. We rebuilt 54 transmission chains involving 209 cases, of which 52.2% were family clusters, and three widespread infection chains were elaborated, occurring in Jining, Zaozhuang and Liaocheng, respectively. The geographical and temporal disparity may alert public health agencies to implement specific measures in regions with different risk, and should attach importance on how to avoid household and community transmission.

Pharmacovigilance and protective medication for drug-induced liver injury in treatment of COVID-19

The outbreak of COVID-19 coronavirus pneumonia in December 2019 has aroused great concern worldwide. At present, the COVID-19 coronavirus pneumonia is highly contagious, rapid and widespread. It has been reported that COVID-19 virus is spread by respiratory droplets and direct contact transmission, and it has various clinical manifestations and recurrent is common. Some patients do not even appear obvious fever and have negative results for throat swab virus culture at the onset of the disease, but the rapid deterioration in their clinical condition usually occurred, which bring difficulties to scientific diagnosis and treatment. At present, western medicine treats most patients with anti-viral drugs, hormones and other drugs, or treats critically ill patients with ECMO oxygenation, important organ function support and other emergency treatments. Traditional Chinese medicine (TCM) based on syndrome differentiation and treatment has obtained curative effects in this outbreak. In order to improve the effects and safety of Chinese and western drug therapy, we applied literature-mining method and network pharmacology, summarized the potential liver injury during the application of western medicine and discussed hepatotoxicity networks and potential pathway targets of ingredients in Chinese patent medicine and Chinese herbal compound. This study not only summarizes essential information regarding potential drug-induced liver injury and biomarkers for pharmacovigilance, but also provides insights for liver protection by TCM or TCM in combination with western medicine in the treatment of novel coronavirus.