Revealing geographic transmission pattern of COVID-19 using neighborhood-level simulation with human mobility data and SEIR model: A Case Study of South Carolina

Direct human physical contact accelerates COVID-19 transmission. Smartphone mobility data has been an emerging data source to reveal fine-grained human mobility, which can be used to estimate the intensity of physical contact surrounding different locations. Our study applied smartphone mobility data to simulate the second wave spreading of COVID-19 in January 2021 in three major metropolitan statistical areas (Columbia, Greenville, and Charleston) in South Carolina, United States. Based on the simulation, the number of historical county-level COVID-19 cases was allocated to neighborhoods (Census blockgroups) and points of interest (POIs), and the transmission rate of each allocated place was estimated. The result reveals that the COVID-19 infections during the study period mainly occurred in neighborhoods (86%), and the number is approximately proportional to the neighborhoods population. Restaurants and elementary and secondary schools contributed more COVID-19 infections than other POI categories. The simulation results for the coastal tourism Charleston area show high transmission rates in POIs related to travel and leisure activities. The results suggest that the neighborhood-level infectious controlling measures are critical in reducing COVID-19 infections. We also found that the households of lower socioeconomic status may be an umbrella against infection due to fewer visits to places such as malls and restaurants associated with their low financial status. Control measures should be tailored to different geographic locations since transmission rates and infection counts of POI categories vary among metropolitan areas.

[Characteristics of Ozone over Standard and Its Relationships with Meteorological Conditions in Beijing City in 2014].

The spatial-temporal distribution characteristics of O3 and the correlations between O3 and meteorological elements in Beijing urban area were investigated based on the hourly O3 monitoring data from January to December in 2014 released by Beijing Municipal Environmental Monitoring Center. The annual concentration of O3 in Beijing was about 56.18 µg·m-3 in 2014. In the over polluted days during May and September, the O3 concentration could reach as high as 148.05 µg·m-3. The diurnal distribution of ozone presented a clear unimodal pattern with its peak appearing at 15:00 or 16:00 and trough at 06:00 or 07:00 and the concentrations of O3 during 09:00 and 23:00 was significantly higher than those in the Summer time. For the spatial distribution of O3, the concentration was lower in central urban area with the highest concentration appearing at plant garden site in the west of the urban area. Ground weather type of O3 over polluted days was divided into three categories including high-pressure, low-pressure, equalizing field, which accounted for 16%, 36%, 48%, respectively. The concentration of O3 was negatively correlated with the air pressure, humidity and visibility while it was positively correlated with the wind speed and temperature. In one heavy pollution episode of O3 caused by local photochemical pollution and regional transport from May 29th to June 1st in 2014 in Beijing, regional transport showed a very important influence on the concentration of O3 in Beijing.

Effects of bromopropane exposure on expression of DNA methyltransferases and level of histone acetylation in testis of male rats / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the changes in the expression of DNA methyltransferases (DNMTs) and activities of histone acetyltransferase (HAT) and histone deacetylase (HDAC) in the testis of male rats exposed to bromopropanes (BPs).</p><p><b>METHODS</b>Twenty-seven male rats were randomly divided into three groups to be intraperitoneally injected with 1-BP,2-BP, or corn oil (as a control) for two weeks. The sperm count and morphology in the epididymis were evaluated. The mRNA expression of DNMT1, DNMT3a, and DNMT3b and activities of HAT and HDAC in the testis were measured by quantitative real-time PCR and ELISA.</p><p><b>RESULTS</b>Compared with the control group, the BP exposure groups showed significant decreased absolute and relative sperm counts; the proportion of tailless sperm increased in the 1-BP exposure group, while the proportion of sperm with abnormal heads increased in the 2-BP exposure group. The 2-BP exposure group had significantly lower mRNA expression of DNMT1, DNMT3a, and DNMT3b than the control group (P < 0.05). There were no significant differences in the activities of HAT and HDAC between the control group and 1-BP exposure group; the 2-BP exposure group showed significantly higher HAT activity than the control group (P < 0.05), but no significant difference was found in HDAC activity between them.</p><p><b>CONCLUSION</b>Exposure to 2-BP might induce abnormal DNA methylation and histone acetylation, and epigenetic regulation might play an important role in the reproductive toxicity of 2-BP.</p>

Effects of rat maternal fenvalerate exposure on behavior development of rat pubertal female offspring / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the effects of rat maternal exposure to fenvalerate during lactation on behaviors development in rat pubertal female offspring.</p><p><b>METHODS</b>Twelve ICR maternal mice were randomly divided into 7.5 and 30.0 mg/kg fenvalerate exposure groups and control group (four dams each group, ten pups each dam, half male half female, twenty female pups each group). The exposure groups were orally exposed to fenvalerate at the doses of 7.5 and 30 mg/kg a day from postnatal day 1 (PND1) to PND21. The control group was exposed to corn oil. The effects of maternal fenvalerate exposure during lactation on motor and species-typical behaviors in female offspring were observed on the PND 35.</p><p><b>RESULTS</b>The peripheral time and standing frequency of 30.0 mg/kg exposure group were (263.4 ± 54.8) s and (47.3 ± 16.2) times, which were significantly higher than those [(203.4 ± 53.0) s and (30.9 ± 17.3) times] of control group (P < 0.05). The scores in 7.5 mg/kg and 30.0 mg/kg exposure groups were 56.50 ± 50.79 and 54.73 ± 53.91, respectively, which were significantly lower than that (114.53 ± 53.87) in control group (P < 0.05). However, no significant differences in beam walking scores, food hoarding quantity, food digging quantity, and nest construction scores between two exposure groups were found (P > 0.05).</p><p><b>CONCLUSION</b>The rat maternal exposure to fenvalerate during lactation could decrease the ability of exploration and motor condition and increase the anxiety but not affect life habit in rat pubertal female offspring.</p>

Effects of pyrrolidine dithiocarbamate on acute apoptotic liver injury in mice / 中国药理学通报

Aim To investigate the effects of pyrrolidine dithiocarbamate (PDTC) on D-galactosamine/lipopolysaccharides (GalN/LPS)-induced acute apoptotic liver injury and its mechanism.Methods All mice were randomly divided into four groups.Mice in GalN/LPS group were co-injected with GalN (600 mg·kg~(-1),ip) and LPS (20 μg·kg~(-1), ip). Mice in PDTC+GalN/LPS group were injected with two doses of PDTC,one (100 mg·kg~(-1), ip) at 24 h before LPS and the other at 2 h before LPS (20 μg·kg~(-1), ip).Mice in control groups were treated with PDTC (100 mg·kg~(-1), ip) or saline. Ten mice in each group were observed for animal survival within 72 h after LPS treatment. Six mice in each group were sacrificed 1.5 h after LPS for collecting blood and isolating livers. The expression of hepatic TNF-α mRNA was determined by reverse transcription and polymerase chain reaction (RT-PCR). Hepatic nuclear factor-κB (NF-κB) binding activity was measured with electrophoretic mobility shift assay (EMSA).Twelve mice in each group were sacrificed 8 h after LPS treatment. Serum was collected for measurement of alanine aminotransferase (ALT) and hepatocellular apoptosis and histological examination.Results Co-injection of GalN and LPS markedly increased serum ALT activity. Histopathological examination of liver sections revealed that GalN/LPS induced hepatic congestion, necrosis and massive macrophages infiltration, and increased the number of TUNEL-positive cells in mouse liver.GalN/LPS treatments, led to 90% mortality within 72 h with severe congestion and necrosis in the liver of all the dead mice. PDTC pretreatment significantly inhibited GalN/LPS-induced hepatic NF-κB activation and TNF-α expression. In contrast, PDTC aggravated GalN/LPS-triggered hepatocellular apoptosis, increased serum ALT activity, exacerbated hepatic hemorrhage and necrosis, and accelerated death.Conclusion PDTC aggravates GalN/LPS-induced acute apoptotic liver injury via inhibiting NF-κB-mediated anti-apoptotic effects.

Effects of Maternal Cypermethrin Exposure during Lactation on Testicles and Steroidogenesis of Weaning Offspring / 环境与健康杂志

Objective To explore the effects of maternal cypermethrin exposure during lactation on testicle development and steroidogenesis of weaning offspring, and to provide a theoretical basis for the toxicity study of cypermethrin on reproduction.Methods Twenty-one healthy pregnant mice(clean animal) were randomly divided into three groups.Maternal mice were orally administered with different doses of cypermethrin [0,6.25 and 25 mg(/kg?d),10 ml/kg] dissolved in corn oil daily from postnatal day 1(PND1) to PND21.Fifteen male pups were randomly selected from each group and sacrificed at PND21 after exposure.The testicle organ coefficients were calculated.Serum testosterone(T) and estrogen(E2),testicle T were measured by radioimmunoassay(RIA).Histopathological changes in the testicle tissues were observed by HE stain.Testicle cells apoptosis was detected by TdT-mediated dUTP nick end labeling(TUNEL).Results A significant decrease was observed in body weight and the testicle organ coefficients in cypermethrin-treated group was in a dose-dependent manner(P0.05).Histological examination showed that maternal cypermethrin exposure markedly decreased the number and layers of spermatogenic cells,increased the inside diameter(ID) of seminiferous tubules,and disturbed the array of spermatogenic cells in testicle sections of pups at PND21.No significant effect on apoptosis of testicle cells was seen.Conclusion Maternal cypermethrin exposure during lactation may damage testicles and steroidogenesis of weaning offspring.