Estimation of the daily soil/dust (SD) ingestion rate of children from Gansu Province, China via hand-to-mouth contact using tracer elements.

A total of 60 children (31 males and 29 females) between the ages of 3 and 12 years were randomly selected from Lanzhou City in Gansu Province, northwest China. Hand (soil/dust) SD samples from these children were collected using hand wipes. We determined the approximate amounts of hand SD and the concentrations of three tracer soil elements (Ce, Y, and V) in these samples. The approximate amounts of hand SD ranged from 42.28 to 173.76 mg, with a median value of 85.42 mg. In addition, the mean amounts of hand SD estimated using the concentrations of Ce, Y, and V in the samples were 4.63, 3.43, and 3.42 mg, respectively. The amount of hand SD varied greatly among the age groups: primary school children had more hand SD than kindergarten children, males had more hand SD than females, and children from rural areas had more hand SD than those from urban areas. The rates of daily ingestion of hand SD for kindergarten and primary school children were estimated to be 7.73 and 6.61 mg/day, respectively.

Digital Industry Financial Risk Early Warning System Based on Improved K-Means Clustering Algorithm.

Corporate financial risks not only endanger the financial stability of digital industry but also cause huge losses to the macro-economy and social wealth. In order to detect and warn digital industry financial risks in time, this paper proposes an early warning system of digital industry financial risks based on improved K-means clustering algorithm. Aiming to speed up the K-means calculation and find the optimal clustering subspace, a specific transformation matrix is used to project the data. The feature space is divided into clustering space and noise space. The former contains all spatial structure information; the latter does not contain any information. Each iteration of K-means is carried out in the clustering space, and the effect of dimensionality screening is achieved in the iteration process. At the same time, the retained dimensions are fed back to the next iteration. The dimensional information of the cluster space is discovered automatically, so no additional parameters are introduced. Experimental results show that the accuracy of the proposed algorithm is higher than other algorithms in financial risk detection.

[Non-carcinogenic Risk Assessment of Cadmium Exposure Through Drinking Water in Chinese Residents Based on Age-stratification Weight].

Drinking water is an important cadmium (Cd) exposure pathway for residents in China. In order to quantitatively characterize the risk of cadmium exposure through drinking water, the Cd concentrations of three main drinking water types in China were collected via systematic literature review. The probability distribution of the exposure parameters was estimated using regression models. The non-carcinogenic risk of cadmium exposure to residents through drinking water was evaluated by Monte Carlo simulation. The results showed that significant differences were found among Cd contents in the three water types. The geometric mean of ρ(Cd) in tap water, untreated underground water, and surface water were (0.48±0.78), (1.07±1.82), and (1.04±1.38) µg·L-1, respectively. The non-carcinogenic risk assessment showed that the median of hazard quotients in all age groups and in the three water types were found to be less than 1. Compared with the exposure dose threshold recommended by the US EPA, the probabilities exceeding the threshold of underground water, surface source water, and tap water were 2.4%, 1.3%, and 1.0%, respectively. Children aged 6-8 had the greatest daily average dose of Cd, and the least exposure dose was found in the 15-17 age group. The result of Monte Carlo simulation based on age-stratification weight showed that people 18-44 years old accounted for 50.8% of the total number of people who exceeded the exposure threshold. In summary, the probability of noncarcinogenic risk caused by Cd exposure through drinking water of Chinese residents was relatively low. However, people in some sub-groups still had a relatively high probability of exceeding the exposure dose threshold. It is necessary to further strengthen the control of cadmium pollution in drinking water in order to reduce the health risk caused by cadmium exposure and ensure drinking water safety.

[Probabilistic Risk Assessment of Arsenic Exposure Through Drinking Water Intake in Chinese Residents].

The total arsenic concentrations of the three main drinking water types in China were determined through a systematic literature review. The distribution models of drinking water exposure parameters for different age groups were obtained using the regression method. The carcinogenic and non-carcinogenic risks of different population groups caused by arsenic exposure through different drinking water types were evaluated by a probabilistic risk assessment. The results showed that the geometric mean of total arsenic content in all the drinking water samples in China was (13.0±38.1) µg·L-1. The highest arsenic content was found in the Inner Mongolia Autonomous Region, followed by Guangxi and Shanxi. Based on the relevant standards for drinking water quality, the probability exceeding the threshold value of groundwater and source water is 23.2% and 18.4%, respectively. According to the results of non-carcinogenic risk assessment, the probability of the residents drinking well water and surface water from the water source area exceeding the daily average exposure dose threshold was 24.0% and 19.5%, respectively. According to the carcinogenic risk assessment, the median of carcinogenic risk caused by arsenic in drinking water in China was 3.22×10-5, which is acceptable. The population group of 18-45 years old had the highest risk, and the median LCR was 1.37×10-5. There was still a certain probability that the LCR of drinking well water and surface water would exceed the acceptable risk level recommended by the US EPA. In conclusion, the potential health risks caused by arsenic exposure through drinking water intake exist among Chinese residents. Further control of the arsenic concentration in drinking water is required to reduce the health risk and improve the safety of drinking water. Meanwhile, it is suggested to strengthen the research on risk threshold to provide a scientific basis for the residents' health protection.

[Refined Assessment of Exposure and Health Risks of Heavy Metals in Water for the Children in Xigu District, Lanzhou].

Water is an important pathway for human exposure to heavy metals. Accurate assessment of the health risks that are related to exposure to heavy metals in drinking and household water are required for the preparation of targeted health risk prevention measures. This study explores and identifies the health risks related to exposure to heavy metals via drinking and household water pathways in Xigu District, Lanzhou, northwestern China, using household water samples and survey data obtained during July-September 2015 (wet season) and December 2015-January 2016 (dry season). During each period, drinking water and household water that were available for use by children aged 0-5 and 6-17 years were sampled and a questionnaire on water-related behavior patterns was completed for each household. Cd, Cr, Pb, and As concentrations were analyzed in all water samples, and were used along with water-related exposure factors from the questionnaires to estimate exposure doses and associated health risks using models recommended by the United States Environmental Protection Agency (US EPA). The results showed that the concentrations of Cd, Cr, Pb, and As in both drinking and household water samples did not exceed the relative thresholds defined in China's national water quality standards. The concentrations of heavy metals in household water were more affected by seasonal factors than of those of drinking water. The non-cancer and cancer risks were in the ranges of 2.82×10-8-2.43×10-2 and 7.55×10-9-3.62×10-5, respectively, which are within acceptable levels, although the non-cancer and cancer risks from drinking water were both higher than of those determined for household water. Furthermore, the non-cancer and cancer risks from household water for children aged 0-5 years were lower than of those for children aged 6-17 years in each period. However, the cancer risk from drinking water for children aged 0-5 years was lower than of that for children aged 6-17 years, whereas the reverse was found for non-cancer risks. This study indicates that Cd, Cr, Pb, and As in drinking and household water did not pose significant detrimental effects to human health, and that the refined exposure assessment used could reduce uncertainties in health risk assessments.

[Size Distribution Characteristics and Inhalation Exposure of Particle-Bound PAHs in an Industrial City].

Atmospheric particulate matter was collected during the heating period and the non-heating period of a typical steel industrial process in Northeast China to study the following:① the size-depended distribution and enrichment characteristics of polycyclic aromatic hydrocarbons (PAHs); ② the deposition concentrations of PAHs of different particle sizes in various organs of the human respiratory system; and 3 the risk from human respiratory exposure. The 14 priority PAHs in the samples were determined by high-performance liquid chromatography (HPLC), and respiratory exposure assessment was conducted by combining the atmospheric particle size fractionation sampling technique with an internal deposition model. The results showed that the PAH concentrations during the heating periods (743.9 ng·m-3) were higher than those during the non-heating periods (169.0 ng·m-3). Most PAH contributions (86.3%-89.9%) were related to fine particles with a diameter ≤ 2.06 µm; medium and low molecular weight PAHs showed two concentration peaks in 1.07-2.06 µm and 7.04-9.99 µm range, respectively. In contrast, high molecular weight PAHs showed a unimodal peak in 1.07-2.06 µm range. Four-ring PAHs accounted for 40% of the total PAHs concentrations. With respect to human exposure, 53.3% and 55.3% of the granular PAHs were deposited in the lungs during the heating and non-heating periods, respectively. The incremental lifetime cancer risk (R) of particulate PAHs in the population was calculated using the concentration in the human respiratory system and the total concentration associated with the particulate matter. The R values for adults ranged between 1.3×10-5 and 2.9×10-5 during the heating period, and between 3.1×10-6 and 6.0×10-6 during the non-heating period. The R values for children during the heating period ranged between 1.0×10-5 and 2.3×10-5, and between 2.4×10-6 and 4.8×10-6 during the non-heating period. The results indicated that particle size greatly affected the concentrations of particles deposited in the respiratory system and the level of carcinogenic risk. The combination of the grading sampling technique and the respiratory system settlement model can effectively avoid the over-evaluation of human respiratory exposure.

[Concentration Characteristics and Assessment of Model-Predicted Results of PM2.5 in the Beijing-Tianjin-Hebei Region in Autumn and Winter].

This paper discusses the concentration characteristics of PM2.5, as well as its relationship with meteorological factors in autumn and winter (from September to the following February), from 2013 to 2018 in the Beijing-Tianjin-Hebei (BTH) region. The accuracy and uncertainty of the air quality forecast models NAQPMS(nested air quality prediction modeling system), CMAQ(community multiscale air quality modeling system), and CAMx (comprehensive air quality model with extensions) were analyzed based on the model-predicted and measured PM2.5 concentration in autumn and winter from 2015 to 2018. The accuracy of NAQPMS, CMAQ, and CAMx during typical heavy air pollution was also tested. Moreover, methods to improve the accuracy of the model forecast were discussed. The results showed that the mean concentrations of PM2.5 in the BTH region were 122, 98, 82, 99, and 65 µg·m-3 in the five autumn and winter periods, respectively. When the air quality index (AQI) exceeded 150 during each autumn and winter, it reached 229, 198, 210, 204, and 180 µg·m-3, respectively. There were 64 occurrences of heavy regional PM2.5 air pollution in autumn and winter from 2013 to 2018. The average duration was longest in the 2013 to 2014 period, and shortest in the 2017 to 2018 period. The peak concentration and average concentration of PM2.5 decreased year on year, except for the period from 2016 to 2017. In autumn and winter, PM2.5 concentration had a relatively close relationship with relative humidity, wind and sunshine duration, compared with a weak relationship with temperature and air pressure. Regional heavy air pollution always happened under the condition of low wind speed(less than 2 m·s-1),higher relative humidity(greater than 65%),and southwest and northeast wind direction. In addition, the heavy air pollution of PM2.5 in BTH in autumn and winter can be effectively forecasted by NAQPMS, CMAQ, and CAMx. The predicted and measured PM2.5 concentration showed a close relationship. The models performed well in forecasting Zhangjiakou, Chengde, and Qinhuangdao, but by contrast overestimated in Tangshan, Shijiazhuang, Baoding, Beijing, and Tianjin. The uncertainty of emission sources, measured and predicted meteorological data, and the atmospheric chemical reaction mechanism may be the main reasons for the overestimate.

Alterations of Fc gamma receptor I and Toll-like receptor 4 mediate the antiinflammatory actions of microglia and astrocytes after adrenaline-induced blood-brain barrier opening in rats.

Blood-brain barrier (BBB) opening occurs under many physiological and pathological conditions. BBB opening will lead to the leakage of large circulating molecules into the brain parenchyma. These invasive molecules will induce immune responses. Microglia and astrocytes are the two major cell types responsible for immune responses in the brain, and Fc gamma receptor I (FcgammaRI) and Toll-like receptor 4 (TLR4) are the two important receptors mediating these processes. Data suggest that activation of the FcgammaRI pathway mediates antiinflammatory processes, whereas activation of TLR4 pathway leads to proinflammatory activities. In the present study, we tested the hypothesis that BBB opening could lead to alterations in FcgammaRI and TLR4 pathways in microglia and astrocytes, thus limiting excessive inflammation in the brain. The transient BBB opening was induced by adrenaline injection through a caudal vein in Sprague-Dawley rats. We found that the FcgammaRI pathway was significantly activated in both microglia and astrocytes, as exhibited by the up-regulation of FcgammaRI and its key downstream molecule Syk, as well as the increased production of the effector cytokines, interleukin (IL)-10 and IL-4. Interestingly, after transient BBB opening, TLR4 expression was also increased. However, the expression of MyD88, the central adapter of the TLR4 pathway, was significantly inhibited, with decreased production of the effector cytokines IL-12a and IL-1beta. These results indicate that, after transient BBB opening, FcgammaRI-mediated antiinflammatory processes were activated, whereas TLR4-mediated proinflammatory activities were inhibited in microglia and astrocytes. This may represent an important neuroprotective mechanism of microglia and astrocytes that limits excessive inflammation after BBB opening.

Lipopolysaccharide up-regulates IL-6R alpha expression in cultured leptomeningeal cells via activation of ERK1/2 pathway.

To clarify the response of leptomeningeal cells to immune stimulation, the effect of lipopolysaccharide (LPS) on expression of IL-6 receptors in the cultured leptomeningeal cells was investigated. The results showed that the expression of IL-6R alpha was invisible in the purified leptomeningeal cells while it was seen in the cells when they were co-cultured with astrocytes. On the other hand, GP130 was moderately expressed in both conditions. Following incubation with different doses of LPS, IL-6R alpha expression in purified leptomeningeal cells was increased in a time- and dose-dependent manner, while GP130 level remained unchanged. Concomitantly, phosphorylated ERK1/2 level was increased following LPS stimulation and its inhibition by PD98059 attenuated the LPS-induced increase of IL-6R alpha expression. These data indicate that leptomeningeal cells can respond to immunogenic stimuli as manifested by expression of cytokine receptors. Moreover, ERK1/2 pathway seems to be involved in the process of LPS-induced IL-6R alpha up-regulation in leptomeningeal cells.

Role of extracellular signal-regulated kinase in glutamate-stimulated apoptosis of rat retinal ganglion cells.

PURPOSE: To investigate the involvement of the extracellular signal-regulated kinase (ERK) signaling pathway after intravitrevous injection of glutamate in rat retina. METHODS: Three groups of five Sprague-Dawley rats each were studied. Group I was a normal control group, intravitreal saline injections. In Group II, one eye received an intravitreal glutamate injection (375 nmol, dissolved in saline) while the contralateral eye served as control. In Group III, intravitreal PD98059 (100 micro mol, an inhibitor of ERK) injections were administered 1 hr before glutamate injections. Seven days after injections, phosphorylated (activated) ERK in retina was localized by immunohistochemistry and fluorescent double labeling of retinal cryosections. Specific ERK blockade was documented to assess the functional significance of activated ERK. TUNEL staining was performed to assess apoptotic cell death. RESULTS: Expression of phosphorylated ERK in rat retina was observed in the inner nuclear layer, the outer nuclear layer, and the nerve fiber layer after 3 days intravitreous injection of glutamate, increasing significantly after 7 days. Double immunofluorescence labling demonstrated that the increased retinal immunostaining for phospho-ERK was predominantly localized to the retinal Müller cells after 7 days intravitreous injection of glutamate. Moreover, blocking activation of ERK significantly improved the number of TUNEL-positive cells in the eyes receiving intravitreal PD98059 injections compared with the eyes receiving glutamate injections. CONCLUSIONS: The ERK pathway is involved in signal transduction in the retina after excessive stimulation by glutamate, which may contribute to the antiapoptotic role in retinal ganglion cell death induced by glutamate.