A field investigation into the characteristics and formation mechanisms of particles during the operation of laser printers and photocopiers.

Indoor particle release from toner printing equipment (TPE) is a major health concern and has received wide attention. In this study, nine printing centers were randomly selected and three working phases were simulated, namely, non-working, normal printing/copying, and heavy printing/copying. The dynamics of the ozone (O3), volatile organic compound (VOC), and particle emissions from TPE were determined by portable detectors. Results showed that particles, VOCs, and O3 were indeed discharged, and particles and VOCs concentrations remained at high levels. Among them, 44% of the rooms represented high-level particle releases. Submicrometer-sized particles, especially nanoparticles, were positively correlated with VOCs, but were inversely proportional to the O3 concentration. Four elements, Ca, Al, Mg and Ni, were usually present in nanoparticles because of the discharge of paper. Si, Al, K, Ni and Pb were found in the submicrometer-sized particles and were consistent with the toner composition. The potential particle precursors were identified, which suggested that styrene was the most likely secondary organic aerosol (SOA) precursor. Overall, the use of the toner formulation and the discharge of paper attribute to the TPE-emitted particles, in which styrene is a specific monitoring indicator for the formation of SOA.

Source-tracking of the Chinese Chikungunya viruses suggests that Indian subcontinent and Southeast Asia act as major hubs for the recent global spread of Chikungunya virus.

BACKGROUND: Chikungunya fever, caused by the Chikungunya virus (CHIKV), has become a major global health concern, causing unexpected large outbreaks in Africa, Asia, Europe, and the Americas. CHIKV is not indigenous to China, and its origin in the country is poorly understood. In particular, there is limited understanding of the recent global spread of CHIKV in the context of the CHIKV epidemic. METHODS: Here we investigated a novel Chikungunya patient who came from Myanmar to China in August, 2019. Direct genome sequencing was performed via combined MinION sequencing and BGISEQ-500 sequencing. A complete CHIKV genome dataset, including 727 CHIKV genomes retrieved from GenBank and the genome sequenced in this study, was constructed. An updated and comprehensive phylogenetic analysis was conducted to understand the virus's origin, evolution, transmission routes and genetic adaptation. RESULTS: All globally distributed CHIKV genomes were divided into West Africa, East/Central/South African and Asian genotypes. The genome sequenced in this study was located in the Indian Ocean lineage, and was closely related to a strain isolated from an Australian patient who returned from Bangladesh in 2017. A comprehensive phylogenetic analysis showed that the Chinese strains mainly originated from the Indian subcontinent and Southeast Asia. Further analyses indicated that the Indian subcontinent and Southeast Asia may act as major hubs for the recent global spread of CHIKV, leading to multiple outbreaks and epidemics. Moreover, we identified 179 distinct sites, including some undescribed sites in the structural and non-structural proteins, which exhibited apparent genetic variations associated with different CHIKV lineages. CONCLUSIONS: Here we report a novel CHIKV isolate from a chikungunya patient who came from Myanmar to China in 2019, and summarize the source and evolution of Chinese CHIKV strains. Our present findings provide a better understanding of the recent global evolution of CHIKV, highlighting the urgent need for strengthened surveillance against viral diversity.

Fatty Liver Disease Caused by High-Alcohol-Producing Klebsiella pneumoniae.

The underlying etiology of nonalcoholic fatty liver disease (NAFLD) is believed to be quite varied. Changes in the gut microbiota have been investigated and are believed to contribute to at least some cases of the disease, though a causal relationship remains unclear. Here, we show that high-alcohol-producing Klebsiella pneumoniae (HiAlc Kpn) is associated with up to 60% of individuals with NAFLD in a Chinese cohort. Transfer of clinical isolates of HiAlc Kpn by oral gavage into mice induced NAFLD. Likewise, fecal microbiota transplant (FMT) into mice using a HiAlc-Kpn-strain-containing microbiota isolated from an individual with NASH induced NAFLD. However, selective elimination of the HiAlc Kpn strain before FMT prevented NAFLD in the recipient mice. These results suggest that at least in some cases of NAFLD an alteration in the gut microbiome drives the condition due to excess endogenous alcohol production.

Investigation and Source Apportionment of Air Pollutants in a Large Oceangoing Ship during Voyage.

The aims of this study were to determine compartmental air pollution during navigation of a large oceangoing ship and to identify preliminarily the major pollution sources. During the voyage of a bulk carrier ship, air samples were collected at 18 selected sites using a stratified sampling method. The concentrations of 15 pollutants were determined using gas chromatography. Results showed the concentrations of these pollutants varied significantly among the sampling sites, indicating major pollution sources at or nearby those locations. Five common factors extracted using factor analysis explained 89.092% of the total variance. Multivariate linear regression analysis showed the contributions to air pollution of these five common factors, i.e., the volatilization of ship paint, volatilization of ship-based oil, cooking activities, high-temperature release of rubber components on the ship and daily use of chemical products, and the application of deodorant and insecticide, were 41.07%, 25.14%, 14.37%, 11.78%, and 7.63%, respectively. Three significant groups were determined using cluster analysis based on their similarity, i.e., high, medium, and low pollution of sampling sites. This study established that the air of the bulk carrier ship was heavily polluted, and that effective identification of pollution sources could provide a scientific basis for its control.

Propoxur enhances MMP-2 expression and the corresponding invasion of human breast cancer cells via the ERK/Nrf2 signaling pathway.

Propoxur is considered a prime etiological suspect of increasing tumor incidence, but the role is still undefined. In this study, two human breast cancer cells lines, MCF-7 and MDA-MB-231 cells, were used as cell models. Cells were respectively treated with 0, 0.01, 1, or 100 µM propoxur. PD98059, a MEK inhibitor, was administered to block the ERK/MAPK pathway. Migration and reactive oxygen species were measured by wound healing and Transwell assays, and flow cytometry. Protein expression and subcellular location were detected by western blotting and immunofluorescence staining, respectively. Results showed that propoxur treatment enhanced cell migration and invasion in a dose-dependent manner, while MMP-2 expression, but not MMP-9, was significantly increased in two cell lines. Meanwhile, the treatment increased intracellular reactive oxygen species, Nrf2 expression and nuclear translocation, and ERK1/2 phosphorylation. Inversely, inhibition of ERK1/2 activation with PD98059 significantly attenuated propoxur-induced Nrf2 expression and nuclear translocation. Moreover, PD98059 suppressed propoxur-induced cell migration and invasion, and MMP-2 overexpression. Collectively, these results indicate that propoxur can trigger reactive oxygen species overproduction, further promoting breast cancer cell migration and invasion by regulating the ERK/Nrf2 signaling pathways.

Impacts of a flash flood on drinking water quality: case study of areas most affected by the 2012 Beijing flood.

In this study, we present a method for identifying sources of water pollution and their relative contributions in pollution disasters. The method uses a combination of principal component analysis and factor analysis. We carried out a case study in three rural villages close to Beijing after torrential rain on July 21, 2012. Nine water samples were analyzed for eight parameters, namely turbidity, total hardness, total dissolved solids, sulfates, chlorides, nitrates, total bacterial count, and total coliform groups. All of the samples showed different degrees of pollution, and most were unsuitable for drinking water as concentrations of various parameters exceeded recommended thresholds. Principal component analysis and factor analysis showed that two factors, the degree of mineralization and agricultural runoff, and flood entrainment, explained 82.50% of the total variance. The case study demonstrates that this method is useful for evaluating and interpreting large, complex water-quality data sets.

[Interference for Various Quench Agents of Chemical Disinfectants on Detection of Endotoxin Activities in Water].

The quenching agents such as histidine, glycine, ascorbic acid, Tween-80, sodium sulfite and sodium hyposulfite are commonly used for quenching the residual disinfectant in water. In this paper, in order to select the optimal type and concentration range of quenching agents prior to the Limulus assays, the interference effects of each quenching agent at different concentrations on endotoxin detection were investigated by the Limulus assays of kinetic-turbidity. Our results identified that, as for 0-1.0% concentration of histidine, ascorbic acid, Tween-80, sodium sulfite (pH unadjusted and pH neutral), interference on the Limulus assays was existed. Hence, these quenching agents could not be applied as neutralizers prior to Limulus assays. Although, there was no interference on endotoxin detection for the glycine, a yellow color, developed by the quenching products of glycine and glutaric dialdehyde, contributed to false positive results. Hence, glycine should not be used as quenching agents in Limulus assays for samples containing glutaric dialdehyde. Compared with other quenching agents as histidine, glycine, ascorbic acid, Tween-80, sodium sulfite, 0-1.0% concentration of sodium hyposulfite elicited no obvious interference, while 1.0%-5.0% concentration of sodium hyposulfite illustrated exhibition effect for endotoxin detection. All in all, compared with other quenching agents as histidine, glycine, ascorbic acid, Tween-80 and sodium sulfite, sodium hyposulfite is suitable for quenching chemicals prior to endotoxin detection and less than 0.5% of concentration is allowable.

Claudin-4 is required for vasculogenic mimicry formation in human breast cancer cells.

Vasculogenic mimicry (VM) refers to the unique capability of aggressive tumor cells to mimic the pattern of embryonic vasculogenic networks. Claudins are aberrantly expressed in aggressive breast cancer. However, the relationship between claudins and VM formation is not clear. We examined VM in two human breast cancer cell lines with different aggressive capabilities (MDA-MB-231 and MCF-7 cells) and one human umbilical vein endothelial cell line (HUVEC). Both HUVEC and MDA-MB-231 cells formed vascular channels in Matrigel cultures, while MCF-7 cells did not. Western blot analysis revealed a possible correlation between claudin-4 and -6 expression in breast cancer cell lines and tumor aggressiveness, with protein levels correlating with the ability to form vascular channels. Treatment of MDA-MB-231 and HUVEC cells with claudin-4 monoclonal antibodies completely inhibited the ability of cells to form vascular channels. Moreover, knockdown of claudin-4 by short hairpin RNA completely inhibited tubule formation in MDA-MB-231 cells. Overexpression of claudin-4 in MCF-7 cells induced formation of vascular channels. Immunocytochemistry revealed that membranous claudin-4 protein was significantly associated with vascular channel formation. Collectively, these results indicate that claudin-4 may play a critical role in VM in human breast cancer cells, opening new opportunities to improve aggressive breast cancer therapy.

[Endotoxin Contamination and Correlation with Other Water Quality Parameters of Groundwater from Self-Contained Wells in Beijing].

A survey of endotoxin activity in groundwater from 14 self-contained wells in PLA units stationed in Beijing was conducted by the kinetic-turbid assay of Tachypleus Amebocyte Lysate (TAL). Bacteriological parameters, including total cell counts detected by flow cytometry, heterotrophic plate counts (HPC), standard plate counts and total coliforms were analyzed. Additionally, suspended particles, turbidity, dissolved organic carbon (DOC), and UV254 were investigated. Total endotoxin activities ranged from 0. 15 to 13.20 EU · mL⁻¹, free endotoxin activities ranged from 0.10 to 5.29 EU · mL⁻¹ and bound endotoxin activities ranged from 0.01 to 8.60 EU · mL⁻¹. Most of the endotoxins in heavily contaminated groundwater existed as bound endotoxins. As for total endotoxins, the sequence of correlation coefficients with other parameters was total cell counts (r = 0.88 ) > HPC (r = 0.79) > DOC (r = 0.77) > UV254 (r = 0.57) > total coliforms (r = 0.50) > standard plate counts (r = 0.49) = turbidity (r = 0. 49) > total particles (r = 0.41). The sequence of correlations of the bound endotoxins with other parameters was total cell counts (r = 0.81) > HPC (r = 0.66) > total coliforms (r = 0.65) > turbidity (r = 0.62) > total particles (r = 0.58) > standard plate counts (r = 0.22). Free endotoxins were correlated with DOC and UV254, r = 0.58 and 0.26, respectively. Result showed free endotoxins had a higher correlation with DOC, and a lower correlation with UV254.

[Review on characteristics and detecting assay of bacterial endotoxin contamination in water environment].

Endotoxins, also known as lipopolysaccharide complexes, are anchored in the outer membrane cell wall of most Gram-negative bacteria and some cyanobacteria. They are continuously released to environment during cell decay. Being common pyrogens and highly immunogenic molecules, endotoxins are related to many human diseases. Due to the tolerances and thermo-stability of endotoxin molecules, they were hard to be removed by common methods. The health risk caused by the endotoxin contamination in drinking water and water environment by various exposure pathways have attracted more and more attention in recent years. In this paper, the physical and chemical properties, biological activities and detection assay of the endotoxin contamination were reviewed, and interfere factors of the main assay, the LAL/TAL (Limulus amebocyte lysate/Tachypleus amebocyte lysate) assay, for detecting endotoxin in water sample were investigated, and the development tendency of the endotoxin detection assay was analyzed.

Higher isolation of NDM-1 producing Acinetobacter baumannii from the sewage of the hospitals in Beijing.

Multidrug resistant microbes present in the environment are a potential public health risk. In this study, we investigate the presence of New Delhi metallo-ß-lactamase 1 (NDM-1) producing bacteria in the 99 water samples in Beijing City, including river water, treated drinking water, raw water samples from the pools and sewage from 4 comprehensive hospitals. For the bla NDM-1 positive isolate, antimicrobial susceptibility testing was further analyzed, and Pulsed Field Gel Electrophoresis (PFGE) was performed to determine the genetic relationship among the NDM-1 producing isolates from sewage and human, as well as the clinical strains without NDM-1. The results indicate that there was a higher isolation of NDM-1 producing Acinetobacter baumannii from the sewage of the hospitals, while no NDM-1 producing isolates were recovered from samples obtained from the river, drinking, or fishpond water. Surprisingly, these isolates were markedly different from the clinical isolates in drug resistance and pulsed field gel electrophoresis profiles, suggesting different evolutionary relationships. Our results showed that the hospital sewage may be one of the diffusion reservoirs of NDM-1 producing bacteria.

Regulation of hepatitis C virus translation initiation by iron: role of eIF3 and La protein.

Eukaryotic initiation factors (eIFs) are required for encoding polyprotein of hepatitis C virus (HCV) which is mediated by an internal ribosome-entry site (IRES). Iron overload, a common finding among HCV patients, may be correlated with HCV pathology, but the underlying molecular mechanisms are poorly understood. In this study, we investigated the possible relationship among iron status, eIFs and HCV IRES-mediated translation in vitro. Using bicistronic reporter gene constructs carrying HCV IRES sequence, we found that the levels of intracellular iron were positively associated with the HCV IRES-dependent translation initiation in Huh-7 cells. RT-PCR method showed that iron treatment specifically increased the levels of eIF3A mRNA and La mRNA, whereas iron chelation reduced them. Western blots also confirmed that iron-dependent changes in eIF3A mRNA and La mRNA affected the expression of their proteins. Moreover, antisense phosphorothioate oligodeoxynucleotides to eIF3A and La successfully suppressed the levels of eIF3A and La protein and significantly reduced iron-dependent HCV translation. Taken together, our results suggest that iron promotes the translation initiation of HCV by stimulating the expression of eIF3A and La proteins. Inhibition of eIF3A and La proteins substantially repressed iron-dependent HCV translation, a beneficial effect that may have significant clinical implications.

Inhibition of translation initiation factors might be the potential therapeutic targets for HCV patients with hepatic iron overload.

Standard therapy, interferon-alpha (IFN-α) and ribavirin, remains the only available option for treatment of patients with hepatitis C virus (HCV) infection. However, iron overload, a common finding among HCV patients, have a poor response to treatment with current therapy. These data suggest that both host and viral factors are involved in the determination of the outcome of the therapy. Currently, novel antiviral compounds focus on the development of indirect antiviral drugs. The process of the viral translation is considered as the potential therapeutic targets. Coincidentally, study has found that hepatic iron load enhances the levels of eukaryotic initiation factor 3 (eIF3), which is essential for HCV translation. Reversely, iron chelation could reduce eIF3 p170 translation. Our hypothesis is that iron overload may specifically enhance cellular eIFs. As a result, the cellular mechanisms, in patients with iron overload, are utilized for translating viral mRNA into protein. Thus, treatment strategies that target eIFs should be an exceptionally good candidate therapeutic method for HCV patients with hepatic iron overload.

Changes of metabolic profiles in urine after oral administration of quercetin in rats.

Quercetin has been studied extensively. However, its actions in vivo are not well understood. We investigated the overall metabolic changes in urine after oral quercetin administration in rats and try to provide useful information on the actions of quercetin in vivo. Rats were orally administered a single dose of quercetin aglycon (40 mg/kg body weight). Urine samples were collected and subjected to (1)H nuclear magnetic resonance (NMR)-based metabolomic analysis and high performance liquid chromatography-mass spectrometry (HPLC-MS). Significant changes of metabolic profiles were observed in urine after quercetin administration. Relative increase in the concentrations of choline, creatinine, dimethylglycine, hippurate, taurine, trimethylamine N-oxide and reduction in acetate, alanine, lactate were observed. The concentrations of citrate, 2-oxoglutarate and succinate increased in the 0-24h period after treatment and decreased thereafter. Some peaks assignable to quercetin metabolites were found in the aromatic regions of (1)H NMR spectra. HPLC-MS analysis identified quercetin, methyl quercetin, quercetin sulfate, quercetin monoglucuronide, and methyl quercetin monoglucuronide in urine after administration of quercetin. Our current findings indicate that quercetin behaves not only as an antioxidant, but also a modulator for some metabolic processes in vivo. The active forms of quercetin present in the biofluids must be investigated further.

[HPLC-MS analysis of quercetin and its metabolites in portal vein after intragastrical administration of quercetin in rats].

OBJECTIVE: To analyse the plasma contents of querceitn and its metabolites in portal vein in rats. METHODS: Male Wistar rats were orally administrated with quercetin at the dose of 40 mg/kg. The blood samples were corrected from the portal vein 1 h later. The quercetin and its metabolites in plasma were analysed with high performance liquid chromatography-mass spetrometry (HPLC-MS) method. RESULTS: The quercetin, quercetin-3-glucuronide, quercetin glucuronide sulfate, 3'-O-methylated quercetin, 4'-O- methylated quercetin and quercetin sulfate were detected in portal vein. CONCLUSION: The results indicated that the quercetin was extensively metabolized in intestine and entered the portal vein in various forms after administration.