Enhanced Desulfurization Performance of ZIF-8/PEG MMMs: Effect of ZIF-8 Particle Size.

Constructing efficient and continuous transport pathways in membranes is a promising and challenging way to achieve the desired performance in the pervaporation process. The incorporation of various metal-organic frameworks (MOFs) into polymer membranes provided selective and fast transport channels and enhanced the separation performance of polymeric membranes. Particle size and surface properties are strongly related to the random distribution and possible agglomeration of MOFs particles, which may lead to poor connectivity between adjacent MOFs-based nanoparticles and result in low-efficiency molecular transport in the membrane. In this work, ZIF-8 particles with different particle sizes were physically filled into PEG to fabricate mixed matrix membranes (MMMs) for desulfurization via pervaporation. The micro-structures and physi-/chemical properties of different ZIF-8 particles, along with their corresponding MMMs, were systematically characterized by SEM, FT-IR, XRD, BET, etc. It was found that ZIF-8 with different particle sizes showed similar crystalline structures and surface areas, while larger ZIF-8 particles possessed more micro-pores and fewer meso-/macro-pores than did the smaller particles. ZIF-8 showed preferential adsorption for thiophene rather than n-heptane molecules, and the diffusion coefficient of thiophene was larger than that of thiophene in ZIF-8, based on molecular simulation. PEG MMMs with larger ZIF-8 particles showed a higher sulfur enrichment factor, but a lower permeation flux than that found with smaller particles. This might be ascribed to the fact that larger ZIF-8 particles provided more and longer selective transport channels in one single particle. Moreover, the number of ZIF-8-L particles in MMMs was smaller than the number of smaller ones with the same particle loading, which might weaken the connectivity between adjacent ZIF-8-L nanoparticles and result in low-efficiency molecular transport in the membrane. Moreover, the surface area available for mass transport was smaller for MMMs with ZIF-8-L particles due to the smaller specific surface area of the ZIF-8-L particles, which might also result in lower permeability in ZIF-8-L/PEG MMMs. The ZIF-8-L/PEG MMMs exhibited enhanced pervaporation performance, with a sulfur enrichment factor of 22.5 and a permeation flux of 183.2 g/(m-2·h-1), increasing by 57% and 389% compared with the results for pure PEG membrane, respectively. The effects of ZIF-8 loading, feed temperature, and concentration on desulfurization performance were also studied. This work might provide some new insights into the effect of particle size on desulfurization performance and the transport mechanism in MMMs.

A Poisoning Outbreak Caused by Anisodus tanguticus - Maqin County, Qinghai Province, China, July 2021.

What is already known about this topic?: Anisodus tanguticus belongs to the Solanaceae family. The plant is toxic due to the tropane alkaloids it contains and can cause poisoning when it is ingested or used inappropriately. What is added by this report?: A poisoning outbreak involved 10 patients, and one death was caused by Anisodus tanguticus. The etiological association of plant exposure and poisoning was confirmed with evidence from an epidemiological investigation, clinical manifestations, plant identification and a toxin analysis. What are the implications for public health practice?: The risk of poisoning caused by mistakenly collecting and ingesting tropane alkaloid-containing plants should be highlighted, and public health practitioners should be on alert.

The generation characteristics, pattern, and exposure risk of bioaerosol emitted in an A²O process wastewater treatment plant.

Bioaerosols can be generated in wastewater treatment plants (WWTPs), they may contain pathogenic bacteria, cause disease transmission, and attract the public's attention. In this study, bioaerosols were collected from seven different stages of an A²O process WWTP. The component characteristics were analyzed by bacterial culture and high-throughput sequencing. The correlations in different processes were analyzed, and the health risks of bioaerosols produced were evaluated. The results showed that the concentration range of bacteria aerosol in the WWTP was 75 CFU/m³-706 CFU/m³. The concentration range of total suspended particles was 111.13 µg/m³-211.67 µg/m³, the primary water-soluble ions were Ca²âº and Cl⁻. In the air of each stage, the main bacteria were Cetobacterium, Bacteroides, Romboutsia, and the fungi were Fusarium, Alternaria, and Aspergillus. The dominant bacteria in the wastewater were Cetobacterium, Romboutsia, Stenotrophobacter, and the fungi were Fusarium, Aspergillus, and Mortierella. The total bacterial concentration and ion concentration in the aerobic section of the biochemical tank were the highest. The results of species composition and principal component analysis showed that the bacterial composition in the air at different processes was similar, while the bacteria in wastewater differed significantly. Among them, the wastewater bacteria in the aerobic section of the biochemical tank were closer to that in the air. Fungal results were similar to bacteria but not prominent. The bioaerosol exposure risk results show that the risk in each stage was acceptable (5.15 ×10⁻4-6.47 ×10⁻³). However, the exposure risk of bioaerosol was calculated by the total bacterial concentration. In fact, some pathogenic microorganisms such as Escherichia coli and Aspergillus flavus were detected in bioaerosols, which may cause hemorrhagic colitis, cancer and other diseases by swallowing and inhalation. Therefore, the risk might be underestimated and should be a cause of concern.

Acute effects of major air pollutants on hospital visits for upper respiratory tract infection in children in Xining District / 中国学校卫生

Objective@#To evaluate the acute effects of air pollutants (PM2.5,SO2 and NO2) on hospital visits for upper respiratory tract infection in children,and provide the reference for goverment to make effective interventional measures and to instruct prevention and protection of children’s health.@*Methods@#Daily meteorological data, air pollutants levels and hospital visits for upper respiratory tract infection in children between 2016 and 2018 were collected for analysis. The generalized linear model (GLM) based on Quasi-Poisson regression was used for estimating the acute effects of each pollutant on hospital visits for upper respiratory tract infection in children. The confounding factors of seasonal trend, long-term trends, meteorological factors, week effect were controlled in the model. The lag pattern of lag days (lag0-lag5) and moving average effect (lag01-lag05) was conducted. The excessive risk (ER) of hospital visits for upper respiratory tract infection in children with 95% confidence interval (95%CI) was calculated with an increase of 10 μg/m3 of PM2.5，SO2 and NO2 respectively.@*Results@#Seasonality was showed in the daily pollutants and hospital visits for upper respiratory tract infection in children from 2016 and 2018 in Xining. The average of annual PM2.5，SO2 and NO2 concentration were (47±28)(15+9)(35±17) μg/m3 respectively. The average number of hospital visits for upper respiratory tract infection in children was seventytwo persons. With an increase of 10 μg/m3 of PM2.5,SO2 and NO2 hospital visits for upper respiratory tract infection in children increased by 0.78% (95%C=0.39%-1.17%), 4.19% (95%CI=3.05%-5.34%) and 1.93% (95%CI=1.15%-2.71%) respectively. The three kinds of air pollutants all had certain lag effect.@*Conclusion@#The main air pollutants PM2.5，SO2 and NO2, have acute effects on hospital visits for upper respiratory tract infection in children in Xining district,thus,the work of preventing and controlling air pollution need to be furthur strengthened.

Retrospective seroepidemiology indicated that human enterovirus 71 and coxsackievirus A16 circulated wildly in central and southern China before large-scale outbreaks from 2008.

BACKGROUND: Large nationwide outbreaks of hand, foot, and mouth disease (HFMD) occurred in China from 2008; most of the cases were in children under 5 years. This study aims to identify the situation of natural human enterovirus 71 (HEV71) and coxsackievirus A16 (CVA16) infections in children before 2008 in China. RESULTS: Retrospective seroepidemiologic studies of HEV71 and CVA16 were performed with 900 serum samples collected from children ≤5 years of age in 2005. The samples were collected from 6 different geographical areas (Anhui, Guangdong, Hunan, Xinjiang, Yunnan, and Heilongjiang provinces) in mainland China. Of the 900 samples, 288 were positive for HEV71; the total positive rate was 32.0% and the geometric mean titer (GMT) was 1:8.5. Guangdong (43.7% and 1:10.8), Xinjiang (45.4% and 1:11.1), and Yunnan (43.4% and 1:12.0) provinces had relatively high rates of infection, while Heilongjiang province (8.1% and 1:4.9) had the lowest rate of infection. On the other hand, 390 samples were positive for CVA16; the total positive rate was 43.4% and the GMT was 1:9.5. Anhui (62.2% and 1:16.0) and Hunan (61.1% and 1:23.1) had relatively high rates, while Heilongjiang (8.0% and 1:4.6) had the lowest rate. Although there is a geographical difference in HEV71 and CVA16 infections, low neutralizing antibody positive rate and titer of both viruses were found in all 6 provinces. CONCLUSIONS: This report confirmed that HEV71 and CVA16 had wildly circulated in a couple provinces in China before the large-scale outbreaks from 2008. This finding also suggests that public health measures to control the spread of HEV71 and CVA16 should be devised according to the different regional characteristics.

[In vitro study on the effect of ribavirin reducing the EV71 replication].

OBJECTIVE: Observe the effect of Ribavirin on reducing the EV71 replication, inactivating EV71 and protecting the RD-A cells against the EV71 infection in vitro. METHODS: Using the EV71 isolated from Anhui Fuyang HFMD outbreak, the effect of Ribavirin on RD-A cells during the EV71 infection was observed. RESULTS: In the experiment of Ribavirin inhibiting the EV71 replication, comparing with the no-Ribavirin-dealed virus control group, the group of 1:640 dilution of Ribavirin delayed the CPE for 2 days, while the normal cell group was growing very well. In the experiment of protecting cell from EV71 infection, comparing with the no-Ribavirin-dealed virus control group, the group of 1:8 dilution of Ribavirin delayed the CPE for 4 days. In the experiment of Ribavirin effect on the inactivation of EV71, the group of 1:40 dilution of Ribavirin delayed the CPE for 2 days comparing with the virus control group. CONCLUSION: Ribavirin could inhibit the replication of the EV71 and inactivate the EV71 in vitro. Additionally, Ribavirin could protect RD-A cells from EV 71 infection. The observation will contribute to EV71 infection control and quick medicine therapy.

[Seroepidemical study of Coxsackievirus A 16, in four provinces, China, 2005].

OBJECTIVE: To study the situation of 1- 5-years-old children's antibody against Coxsackievirus A group 16 strain (CVA16) in Guangdong, Heilongjiang,Yunnan Province and Xinjiang Uygur Autonomous Regions, China, 2005, it can offer scientific evidences for preventing and controlling CVA16 causative hand-food and mouth disease. METHODS: Using microneutrilization test, to study 503 serum samples randomly selected from sera collected in 2005. RESULTS: Positive rate of anti-CVA16 antibody were 41.90%, 9.40%, 40.00% and 34.40% in Guangdong, Heilongjiang,Yunnan and Xinjiang, respectively. Antibody titer was relative low (average, 1: 6.1) and there was no statistical difference of geometry mean of antibody titer (GMT) among Guangdong, Heilongjiang, Yunnan (F = 0.97, 0.40, 1.06, respectively; P > 0.05), while there had statistical difference of GMT between Heilongjiang and other three regions( F = 10.61, P < 0.00). CONCLUSIONS: There had probably existed local epidemic in some regions of Guangdong, Heilongjiang, Yunnan Province and Xinjiang Uygur Autonomous Regions, China, 2005 or even before, but the area and degree of transmission and epidemic had difference. Children aged from 1- 5-years-old were relatively susceptible population of CVA16 infection.

[Analysis epidemiological and pathogen characters of mumps in China from 2004 to 2006].

OBJECTIVE: The study was conducted to analyze the epidemiological characteristics of mumps in China (Hong Kong, Macau and Taiwan excluded) from 2004 to 2006 and to provide basic data for mumps control. METHODS: Descriptive epidemiological analysis was conducted based on the data of epidemic parotitis from National Notifiable Disease Reporting System and mumps virus surveillance database from Nation Measles Lab. RESULTS: The annual incidence rates of parotitis cases during 2004-2006 were 17.45/100, 000, 22.40 /100, 000, 20.76 /100, 000 respectively. All the provinces had parotitis cases report. In all parotitis cases during 2004-2006, the percentage of case number of children (< 15 years old) were 89.77%, 87.87%, 85.15% respectively, while the children between 5-9 years old were 49. 16%, 46.90%, 43.26% respectively. The homology based on 316 nucleotides of the Chinese mumps virus isolated during 2004 - 2006 was 95.4%-100%. CONCLUSION: To prevent and control mumps, the mumps surveillance for serology, virology and eoidemiology should be strengthened in China.

[Seroepidemiology investigation of HEV71 in healthy children of 1-6 years old in three counties of China in 2005].

OBJECTIVES: To investigate human enterovirus 71(HEV71) antibody levels among children in China in recent years, to find the epidemic status of hand, foot and mouth diseases (HFMD) in children, and to provide a scientific base for the HFMD prevention and control. METHODS: 371 sera specimens were colleted from 371 children of 1-6 years old in 3 counties of 3 provinces in 2005. All sera proposed to be detected for measles antibodies investigation. HEV71 antibody was detected by using neutralization test, and then the results were analyzed by statistic methods. RESULTS: 164 sera were positive for HEV71 antibody, the positive rate was 44.2%. The distribution of HEV71-positive rate was associated with age of the children, the positive rate was increasing with the age increasing. Children under 3 years old had lower antibody positive rate. The GMT decreased with the increasing of ages. CONCLUSION: HEV71 infections occurred among children in 3 counties of 3 provinces before 2005, and children under 3 years old were main susceptible population due to their low HEV71 antibody level, It is important to take the preventive measures to protect them from HFMD.

[Analysis of epidemiological and genetic characteristics of rubella viruses in China from 2007 to 2008].

OBJECTIVE: To understand the epidemiological and genetic characteristics of rubella viruses in China (excluded Hongkong, Macao and Taiwan areas, the same below) from 2007 to 2008, and to provide the basis for the development of rubella immunization strategy. METHODS: Both rubella epidemiology data from rubella disease surveillance information management system and rubella virology data from National measles Laboratory surveillance data base were analyzed. RESULTS: The reported rubella incidence rate was 5.70/100,000 in 2007 and 9.11/100,000 in 2008 and the reported cases distributed in the whole country. The predominant proportions of rubella cases were <15-years-old children which accounted for 80.94% and 81.85% of total cases in 2007 and 2008 respectively. And the highest number of cases belong to 6-10 age groups, which accounted for 43.24% and 44.13% of total cases in 2007 and 2008 respectively. 1E genotype was the predominant genotype of rubella viruses in China during 2007-2008, and the nucleotide homology of the rubella isolates was 98.1%-100%. CONCLUSION: The rubella Serology diagnosis, virological and serological surveillance should be strengthened. Practicable vaccine immunization strategy for different age groups should be established to achieve the goal of prevention and control of rubella and congenital rubella syndrome.

[Use of three-dimensional fluorescence deconvolution microscopy for study of spatial distribution of secretory vesicles in living cells].

A three-dimensional image of a living cell is helpful for cell secretion study. In this report, the three-dimensional fluorescence deconvolution microscopy for observing living cells was studied, because this technique can obtain a quick three-dimensional imaging with minimal fluorescence quenching and cytotoxicity for living cell observation. The property of three-dimensional point spread function (PSF) of imaging system was analyzed. The relationship between experimental and theoretical PSF was illustrated, and the theoretical PSF was proved that it could reflect the principle of imaging system with NA 1.65 objective in use. Three-dimensional deconvolution algorithm in this report was proved effective by well-defined three-dimensional specimens. Furthermore, the rat pancreatic beta cell secretory vesicles labeled by acridine orange was observed by using this technique. Results showed that the blurring induced by out-of-focus light was removed by the deconvolution algorithm effectively, under current experiment conditions (with NA 1.65 objective) the experimental PSF approximated the theoretical PSF very well, and deconvolved living cell images exhibited the spatial distribution of the secretory vesicles clearly.

[Study on DNA damage in rat bone marrow cells induced by mustard gas].

OBJECTIVE: To study the damage of DNA in rat bone marrow cells induced by mustard gas. METHOD: Male SD rats were randomly divided into six groups. Physiological saline, propylene glycol and mustard gas(0.2, 0.4, 0.8, 1.6 mg/kg) were given separately by i.p. injection. 5 rats in each group were killed after 0, 24, 48, 72 hours of exposure. The DNA damage in rat bone marrow cells was assayed by single cell gel electrophoresis (SCGE). RESULTS: There is no significant difference of DNA damage among all groups at 0 h(P > 0.05). The rates of DNA migration and the lengths of DNA migration of the rat bone marrow cells in propylene glycol group at 24, 48, 72 hours were 15.4% +/- 0.21%, 16.0% +/- 0.19%, 15.7% +/- 0.23% and (11.4 +/- 0.2), (13.5 +/- 0.3), (12.8 +/- 0.2) micron respectively, and they were significantly higher than those of physiological saline group at the same time(P < 0.05). The rates of DNA migration and the lengths of DNA migration of the rat bone marrow cells in mustard gas groups at 24, 48, 72 hours were significantly higher than those in physiological saline group and propylene glycol group at the same time(P < 0.05). CONCLUSION: Mustard gas could induce DNA damage in rat bone marrow cells. The damage was likely to rise as the dose increased and was time-dependent.