Although the COVID-19 is known to cause by human-to-human transmission, it remains largely unclear whether ambient air pollutants and meteorological parameters could promote its transmission. A retrospective study is conducted to study whether air quality index (AQI), four ambient air pollutants (PM2.5, PM10, NO2 and CO) and five meteorological variables (daily temperature, highest temperature, lowest temperature, temperature difference and sunshine duration) could increase COVID-19 incidence in Wuhan and XiaoGan between Jan 26th to Feb 29th in 2020. First, a significant correlation was found between COVID-19 incidence and AQI in both Wuhan (R2 = 0.13, p < 0.05) and XiaoGan (R2 = 0.223, p < 0.01). Specifically, among four pollutants, COVID-19 incidence was prominently correlated with PM2.5 and NO2 in both cities. In Wuhan, the tightest correlation was observed between NO2 and COVID-19 incidence (R2 = 0.329, p < 0.01). In XiaoGan, in addition to the PM2.5 (R2 = 0.117, p < 0.01) and NO2 (R2 = 0.015, p < 0.05), a notable correlation was also observed between the PM10 and COVID-19 incidence (R2 = 0.105, p < 0.05). Moreover, temperature is the only meteorological parameter that constantly correlated well with COVID-19 incidence in both Wuhan and XiaoGan, but in an inverse correlation (p < 0.05). AQI, PM2.5, NO2, and temperature are four variables that could promote the sustained transmission of COVID-19.

Objective: To determine whether ambient air pollutants and meteorological variables are associated with daily COVID-19 incidence.Design: A retrospective cohort from January 25 to February 29, 2020.Setting: Cities of Wuhan, Xiaogan, and Huanggang, China.Patients: The COVID-19 cases detected each day.Methods: We collected daily data of COVID-19 incidence, 8 ambient air pollutants (particulate matter of ≤2.5 µm [PM_2.5], particulate matter ≤10 µm [PM₁₀], sulfur dioxide [SO₂], carbon monoxide [CO], nitrogen dioxide [NO₂], and maximum 8-h moving average concentrations for ozone [O₃-8h]) and 3 meteorological variables (temperature, relative humidity, and wind) in China’s 3 worst COVID-19–stricken cities during the study period. The multivariate Poisson regression was performed to understand their correlation.Results: Daily COVID-19 incidence was positively associated with PM_2.5 and humidity in all cities. Specifically, the relative risk (RR) of PM_2.5 for daily COVID-19 incidences were 1.036 (95% confidence interval [CI], 1.032–1.039) in Wuhan, 1.059 (95% CI, 1.046–1.072) in Xiaogan, and 1.144 (95% CI, 1.12–1.169) in Huanggang. The RR of humidity for daily COVID-19 incidence was consistently lower than that of PM_2.5, and this difference ranged from 0.027 to 0.111. Moreover, PM₁₀ and temperature also exhibited a notable correlation with daily COVID-19 incidence, but in a negative pattern The RR of PM₁₀ for daily COVID-19 incidence ranged from 0.915 (95% CI, 0.896–0.934) to 0.961 (95% CI, 0.95–0.972, while that of temperature ranged from 0.738 (95% CI, 0.717–0.759) to 0.969 (95% CI, 0.966–0.973).Conclusions: Our data show that PM_2.5 and humidity are substantially associated with an increased risk of COVID-19 and that PM₁₀ and temperature are substantially associated with a decreased risk of COVID-19.

BACKGROUND: Endovascular thrombectomy is an effective treatment for acute ischemic stroke, and accurate determination of thrombus length (TL) remains pivotal to successful endovascular thrombectomy. However, to date, no modality could estimate the TL with sufficient efficiency, especially in the emergent setting. In the current study, we presented a novel microcatheter design known as the Tip-End Multi-Side Orifices (TIMSO) microcatheter, which could provide real-time TL assessment. METHODS: The efficacy of the TIMSO was initially validated in an endovascular simulator with continuous saline circulation. After the TIMSO passed the sham thrombus, colored saline was injected through the TIMSO. The length of the ink defect region was integrated with the sham TL. Subsequently, in the live swine acute ischemic stroke model, the efficacy of TIMSO was further evaluated under digital subtraction angiography. RESULTS: In the simulation, a strong positive correlation was observed between the actual TL and the length indicated by the TIMSO (n=20, R ²=0.95, P <0.01). In the in vivo test, the TIMSO could also demonstrate TL (n=10). Interestingly, the TIMSO also detected tandem thrombi, newly formed emboli associated with thrombus fragmentation, and the precise arterial branches towards which the thrombi tend to migrate at arterial bifurcations. CONCLUSIONS: Conclusively, the TIMSO microcatheter could facilitate real-time assessment of TL during endovascular thrombectomy. Furthermore, TISMO has the capacity to discern special embolization scenarios. These characteristics of TIMSO have the potential to contribute to the facilitation of endovascular thrombectomy in future clinical practice.

The authors have withdrawn this preprint due to author disagreement.