Influence and mechanism of the vertical distribution of Cu, Cd, and Pb at a simulated sediment-water interface covered by degradable microplastics.

Currently research on microplastics in the environment focuses on non-degradable microplastics with little attention to research on degradable microplastics. This study involved a 400-day experiment in a simulated lake environment of three degradable microplastics, poly(ε-caprolactone) (PCL), polybutylene succinate (PBS), and poly(butylene adipate terephthalate) (PBAT) at the sediment water interface. Results showed that (1) for the three microplastics, Cd concentration showed a large change from 0 to 20 mm in the water above the sediment interface; the adsorption of Cd, Pb, and Cu in a diffusive gradients thin film (DGT) device are the highest in PBAT micro plastic, followed by PCL and then PBS. (2) Diffuse flux (J) of the three degradable microplastics indicated that Cu, Cd, and Pb in the sediments come from the overlying water that was added to the simulation experiment. (3) Fourier transform infra-red spectroscopy (FTIR) for investigating the adsorption capacity of Cu, Cd, and Pb in the three degradable microplastics showed the absorption peak intensity increased and widened, and some adsorption sites changed. (4) Correlation analysis showed that the factors which most influenced diffusion flux for both water and sediments are oxidation-reduction potential (ORP), followed by organic matter (OM), pH, and electrical conductivity (EC).

Sources Identification and Health Risk Evaluation of 10 Heavy Metals (Metalloids) in Soils of the Aibi Lake Basin, Northwest China.

Recently, soils heavy metals pollution and health risks researches in oasis are few, and in this study, the Aibi lake basin-a typical oasis-was chosen as the research area, and then, we evaluated the pollution status and sources identification and analyzed the health risks of ten heavy metals in the soils. Results showed that (1) the average (range) values for As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, and Zn were (6.500-48.040) 20.011, (0.0002-0.088) 0.035, (0.060-18.150) 5.994, (24.160-106.400) 53.557, (3.460-58.760) 16.981, (0.0002-0.099) 0.042, (195.310-842.850) 483.311, (0.960-70.100) 14.235, (0.180-25.390) 8.086, and (22.340-156.250) 61.334 mg/kg, respectively, and we can get except for As, the maximum values of other nine elements all within the limited values provided by the soil environmental quality risk control standard of China. (2) Health risk evaluation showed that the total exposure amount for ADIing for children and adults was 0.001067998 and 0.000344707, ADIinh for children and adults was 9.69977E-08 and 7.95869E-08, ADIderm for children and adults was 8.52275E-06 and 2.09927E-06, and the order of exploring ways is ADIing > ADIinh > ADIderm. (3) The multivariate statistical analysis and PMF results showed that Cr, Cu, Co, Mn, Ni, Pb, and Zn primarily come from the natural background and man-made sources; Cd primarily comes from man-made sources; As and Hg come from natural background sources and industry sources. The results can provide reference values for heavy metals pollution prevention and the protection of the environment in the Aibi lake basin and as well as central Asia.

Plasma cell-free DNA promise disease monitoring and tissue injury assessment of COVID-19

COVID-19 is a huge threat to global health. Due to the lack of definitive etiological therapeutics currently, effective disease monitoring is of high clinical value for better healthcare and management of the large number of COVID-19 patients. In this study, we recruited 37 COVID-19 patients, collected 176 blood samples upon diagnosis and during treatment, and analyzed cell-free DNA (cfDNA) in these samples. We report gross abnormalities in cfDNA of COVID-19 patients, including elevated GC content, altered molecule size and end motif patterns. More importantly, such cfDNA characteristics reflect patient-specific physiological conditions during treatment. Further analysis on tissue origin tracing of cfDNA reveals frequent tissue injuries in COVID-19 patients, which is supported by clinical diagnoses. Hence, we demonstrate the translational merit of cfDNA as valuable analyte for effective disease monitoring, as well as tissue injury assessment in COVID-19 patients.

Characterization of Microbial Co-infections in the Respiratory Tract of hospitalized COVID-19 patients

BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic of Coronavirus disease 2019 (COVID-19). However, microbial composition of the respiratory tract and other infected tissues, as well as their possible pathogenic contributions to varying degrees of disease severity in COVID-19 patients remain unclear. MethodBetween January 27 and February 26, 2020, serial clinical specimens (sputum, nasal and throat swab, anal swab and feces) were collected from a cohort of hospitalized COVID-19 patients, including 8 mildly and 15 severely ill patients (requiring ICU admission and mechanical ventilation), in the Guangdong province, China. Total RNA was extracted and ultra-deep metatranscriptomic sequencing was performed in combination with laboratory diagnostic assays. Co-infection rates, the prevalence and abundance of microbial communities in these COVID-19 patients were determined. FindingsNotably, respiratory microbial co-infections were exclusively found in 84.6% of severely ill patients (11/13), among which viral and bacterial co-infections were detected by sequencing in 30.8% (4/13) and 69.2% (9/13) of the patients, respectively. In addition, for 23.1% (3/13) of the patients, bacterial co-infections with Burkholderia cepacia complex (BCC) and Staphylococcus epidermidis were also confirmed by bacterial culture. Further, a time-dependent, secondary infection of B. cenocepacia with expressions of multiple virulence genes in one severely ill patient was demonstrated, which might be the primary cause of his disease deterioration and death one month after ICU admission. InterpretationOur findings identified distinct patterns of co-infections with SARS-CoV-2 and various respiratory pathogenic microbes in hospitalized COVID-19 patients in relation to disease severity. Detection and tracking of BCC-associated nosocomial infections are recommended to improve the pre-emptive treatment regimen and reduce fatal outcomes of hospitalized patients infected with SARS-CoV-2. FundingNational Science and Technology Major Project of China, National Major Project for Control and Prevention of Infectious Disease in China, the emergency grants for prevention and control of SARS-CoV-2 of Ministry of Science and Technology and Guangdong province, Guangdong Provincial Key Laboratory of Genome Read and Write, Guangdong Provincial Academician Workstation of BGI Synthetic Genomics, and Shenzhen Engineering Laboratory for Innovative Molecular Diagnostics.

Population Bottlenecks and Intra-host Evolution during Human-to-Human Transmission of SARS-CoV-2Population Bottlenecks and Intra-host Evolution during Human-to-Human Transmission of SARS-CoV-2

The emergence of the novel human coronavirus, SARS-CoV-2, causes a global COVID-19 (coronavirus disease 2019) pandemic. Here, we have characterized and compared viral populations of SARS-CoV-2 among COVID-19 patients within and across households. Our work showed an active viral replication activity in the human respiratory tract and the co-existence of genetically distinct viruses within the same host. The inter-host comparison among viral populations further revealed a narrow transmission bottleneck between patients from the same households, suggesting a dominated role of stochastic dynamics in both inter-host and intra-host evolutions. Author summaryIn this study, we compared SARS-CoV-2 populations of 13 Chinese COVID-19 patients. Those viral populations contained a considerable proportion of viral sub-genomic messenger RNAs (sgmRNA), reflecting an active viral replication activity in the respiratory tract tissues. The comparison of 66 identified intra-host variants further showed a low viral genetic distance between intra-household patients and a narrow transmission bottleneck size. Despite the co-existence of genetically distinct viruses within the same host, most intra-host minor variants were not shared between transmission pairs, suggesting a dominated role of stochastic dynamics in both inter-host and intra-host evolutions. Furthermore, the narrow bottleneck and active viral activity in the respiratory tract show that the passage of a small number of virions can cause infection. Our data have therefore delivered a key genomic resource for the SARS-CoV-2 transmission research and enhanced our understanding of the evolutionary dynamics of SARS-CoV-2.

Intra-host Variation and Evolutionary Dynamics of SARS-CoV-2 Population in COVID-19 Patients

As of middle May 2020, the causative agent of COVID-19, SARS-CoV-2, has infected over 4 million people with more than 300 thousand death as official reports1,2. The key to understanding the biology and virus-host interactions of SARS-CoV-2 requires the knowledge of mutation and evolution of this virus at both inter- and intra-host levels. However, despite quite a few polymorphic sites identified among SARS-CoV-2 populations, intra-host variant spectra and their evolutionary dynamics remain mostly unknown. Here, using deep sequencing data, we achieved and characterized consensus genomes and intra-host genomic variants from 32 serial samples collected from eight patients with COVID-19. The 32 consensus genomes revealed the coexistence of different genotypes within the same patient. We further identified 40 intra-host single nucleotide variants (iSNVs). Most (30/40) iSNVs presented in single patient, while ten iSNVs were found in at least two patients or identical to consensus variants. Comparison of allele frequencies of the iSNVs revealed genetic divergence between intra-host populations of the respiratory tract (RT) and gastrointestinal tract (GIT), mostly driven by bottleneck events among intra-host transmissions. Nonetheless, we observed a maintained viral genetic diversity within GIT, showing an increased population with accumulated mutations developed in the tissue-specific environments. The iSNVs identified here not only show spatial divergence of intra-host viral populations, but also provide new insights into the complex virus-host interactions.

Epidemic and clinical characteristics of 1 976 children with hand-feet-mouth disease in Chengdu, 2018 to 2019 / 中华传染病杂志

Objective:To analyze the epidemiological and clinical characteristics of hand-feet-mouth disease (HFMD).Methods:The clinical and pathogenic data of 1 976 cases with HFMD hospitalized in Public Health Clinical Center of Chengdu from August 2018 to September 2019 were retrospective analyzed.Results:Among the 1 976 cases of HFMD, 1 094 cases (55.36%) were one to two years old, and 803 cases (40.64%) lived in the main urban area. The majority were scattered patients (1 344 cases, 68.02%). There were 1 348(72.7%) of 1 854 cases mainly infected by Coxsackie virus 6 (CV-A6). The main distribution of rashes in children infected by CV-A6 were palm/soles, trunks, limbs, oral ulcer and perioral areal, lips and hip. The types of rash were maculopapule, vesicle, and bulla. Fever (1 543 cases, 78.09%) was the main concomitant symptom. Acute tonsillitis (811 cases, 41.04%), myocardial injury (767 cases, 38.82%), and herpetic angina (658 cases, 33.30%) were the most common complications. The incidence of onychomadesis were nine (7.03%) among the 128 patients during follow-up.Conclusions:CV-A6 is the main pathogen of the HFMD prevalence. Children less than two years old are susceptible and the main symptoms of HFMD are rash and fever.

Pollution assessment and health risks evaluation of (metalloid) heavy metals in urban street dust of 58 cities in China.

In this research, we conducted a statistical analysis of ten (metalloid) heavy metals, including Cu, Hg, Cd, Zn, Pb, As, Ni, Cr, Co, and Mn in urban dust of 58 cities in China from 2000 to 2018, and then we analyzed the statistic characters, pollution statue, and health risks of ten heavy metals. Results showed that (1) the maximum (average) values of ten (metalloid) heavy metals in the street dust of 58 Chinese cities all exceeded Chinese background values, and there were obvious differences in contents of heavy metals of Hg, Zn, Co, Cr, and As between industry cities and common cities. A provincial spatial distribution analysis revealed large variations of distributions of heavy metals Cu, Zn, Pb, and Cr, which distributed in cities mainly located in southern, central, and eastern China, ranging from relatively low to high levels, while Ni, Co, and Mn mainly distributed in southern and central China. This is mainly associated with the mining of the cities. (2) Igeo analysis showed that there was no obvious Ni, Mn, or Co pollution in street dust, while the other tested heavy metals had a range of low to high levels of pollution, in particular, seven metals among them had low to extremely strong levels of pollution (Igeo values between 0 and 7.154), and the average Igeo values were in the following order: Cd > Hg > Zn > Pb > Cu > As>Cr > Mn > Co > Ni. (3) Health risks evaluation showed that of the three exposure ways, the HQing from hand-mouth intake was the most common exposure route for both children and adults, especially for children, followed by skin absorption and respiration ways. This research showed that the HI value for children was higher than 1, indicative of no carcinogenic risks, while the HI values for both male and female were lower than 1, indicative of carcinogenic risks; calculation of carcinogenic risk through respiratory route showed that the risks of five elements were within the range 10-6-10-4, indicative of carcinogenic risk, among which Cr accounting exceeded 90% of total, which needs to be paid more attention to.

Heavy metal pollution assessment, source identification, and health risk evaluation in Aibi Lake of northwest China.

This study sought to analyze heavy metal (Pb, Zn, Cu, Ni, Mn, and Fe) pollution status in the waters of Aibi Lake in northwest China through the use of an applied comprehensive pollution index, health risk model, and multivariate statistical analyses in combination with the lake's land use types. Results showed that (1) the maximum (average) values of the heavy metals Pb, Zn, Cu, Ni, Mn, and Fe were 0.0644 (0.0123), 0.0006 (0.0002), 0.0009 (0.0032), 0.1235 (0.0242), 0.0061 (0.0025), and 0.0222 (0.0080) µg/L, respectively. Among these, in all the samples, Pb and Ni exceeded the standard and acceptable values put forth by the World Health Organization by 21.13 and 25.67%, respectively. Ni also exceeded (30.16%) the third grade of the Environmental Quality Standards for Surface Water of China. The levels of the six heavy metals were all within the fishery and irrigation water quality standard ranges in China. (2) The average values for single pollution index of heavy metals Pb, Zn, Cu, Ni, Mn, and Fe were 1.000, 0.0006, 0.0009, 3.000, 0.060, and 0.070, respectively, among which Ni levels indicated moderate to significant pollution, while others indicated healthy levels. (3) Health risk evaluation showed that the Rn values for Pb, Zn, Cu, Mn, and Fe were 1.8 × 10-4, 5.33 × 10-9, 4.80 × 10-7, 1.08 × 10-6, and 2.51 × 10-7 a-1, respectively, of which, in all samples, Pb and Ni contents all exceeded the maximum acceptable risk levels according to the International Commission on Radiological Protection (ICRP) as well as the U.S. Environment Protection Agency. (4) Combining with multivariate statistical analyses along with the land use distribution within the lake basin, Pb, Zn, Cu, Ni, and Mn were mainly influenced by the agriculture production and emission from urban lives and traffics, and Fe mainly originated from the natural environment. The results of this research can provide reference values for heavy metal pollution prevention in Aibi Lake as well as for environmental protection of rump lakes in the arid regions of northwest China and Central Asia.

Health risk evaluation of heavy metals in green land soils from urban parks in Urumqi, northwest China.

Here, we sampled, tested, and analyzed heavy metals in soil obtained from green land in urban parks of Urumqi. Analysis included soil nutrient contents, particle size distribution, and health risks of heavy metal contaminants. Results showed that (1) organic matter and rapidly available phosphorus contents of all samples ranged from 6.07-58.34 and 6.52-116.15 mg/kg, with average values of 31.26 and 36.24 mg/kg, respectively; (2) silt (particle size 20-200 µm) comprised most of the particle distribution, accounting for 46.56-87.38% of the total, and the remaining particles were clay particles (0-20 µm) and sand (200-2000 µm); (3) calculations of HQing, HQinh, and HQderm for eight heavy metals in three exposure patterns revealed values less than 1 for children and adults, indicating a level of carcinogenic risk for these heavy metals; and (4) calculating the carcinogenic risks of nickel, chromium, and cadmium through breathing pathway indicating no potential carcinogenic risk for any of the three. This research showed high soil nutrient content, providing fertile ground for plant growth in the green land of these urban parks. However, measures such as using sprinklers and increased green vegetation areas have been proposed to improve soil texture. This research can serve as a reference point for soil environmental protection efforts as well as future plant growth in urban Urumqi parks.

A case-control study to identify risk factors associated with carbapenem resistant Enterobacteriaceae nosocomial infection / 国际检验医学杂志

Objective To investigate the characteristics of nosocomial infection of carbapenem resistant En-terobacteriaceae ,then to study the risk factors and prognosis of patients ,as to provide evidence for effective control of CRE hospital infection .Methods A retrospective epidemiology study was conducted of CRE infec-ted patients from January 2016 to June 2017 .This was a 1∶2 matched case-control study of patients with in-fection due to carbapenem resistant Enterobacteriaceae and randomly select 218 patients with non CRE infec-tion in the same hospital as control group ,then the risk factors of CRE infection were investigate .Results A-mong the 109 cases CRE infection patients ,the most common bacteria were Klebsiella pneumoniae ,Enter-obacter cloacae and Escherichia coli .The CRE strains were more sensitive to minocycline than other common antibiotics ,the resistance rate to other antibiotics was more than 40% .Univariate analysis showed that ICU staying time more than 7 d ,using beta lactamase inhibitors and carbapenem antibiotics ,combination therapy and mechanical ventilation were the potential risk factors of CRE nosocomial infection .The non conditional multivariate Logistic regression analysis showed that Check in ICU more than 7 d (OR＝ 4 .981 ,95% CI 2 .451-10 .122 ) ,the use of containing beta lactamase inhibitor antibiotics (OR＝ 3 .718 ,95% CI 2 .162-6 .394) ,use of carbapenem antibiotics (OR＝3 .232 ,95% CI 1 .879-5 .561) ,and mechanical ventilation (OR＝5 .26 ,95% CI 2 .576-10 .742) were independent risk factors of CRE nosocomial infection .The nosocomial in- fection CRE strain was with highly antibiotic resistance rate ,and the average hospitalization time and mortality were significantly higher than those of the control group .Conclusion The carbapenem resistant Enterobacte-riaceae infection had multiple independent risk factors ,strengthening of these independent risk factor control can effectively prevent the spread of CRE isolates infection .

Dynamic monitoring of anti-poliovirus neutralizing antibody and anti-hepatitis A virus IgG antibody in healthy children immunized with inactivated enterovirus 71 vaccine (human diploid cell) / 中华微生物学和免疫学杂志

Objective To investigate the dynamic changes of three types of anti-poliovirus neutralizing antibodies and anti-hepatitis A virus (HAV) IgG antibody in children who were immunized with inactivated enterovirus 71 (EV71) vaccine (human diploid cell).Methods Serum samples were collected from the subjects immunized with inactivated EV71 vaccine.Neutralizing antibodies against EV71 and poliovirus were detected by micro-cytopathic effect neutralization test.Enzyme linked immunosorbent assay (ELISA) was used to detect IgG antibody against HAV.Results The geometric mean titers (GMTs) of anti-EV71 neutralizing antibody increased to 4.85 following the first-dose injection of inactivated EV71 vaccine.A significant increase of GMTs (up to 64.37) could be observed 28 days after the second-dose vaccination.Meanwhile, results of the dynamic monitor showed that there were slight fluctuations in the neutralizing antibodies against three types of poliovirus on day 28 (28 days after the first-dose vaccination) compared with those on day 0 (before vaccination) (P0.05).The level of anti-HAV IgG antibody was stable and no significant difference was found during the observation period (P>0.05).Conclusion This study shows that inactivated EV71 vaccine has no impact on anti-HAV IgG antibody in Children during the two-dose vaccination and in anti-EV71 antibody-producing period, but has slight influence on the anti-poliovirus antibodies.In general, changes in antibody profile do not affect the clinical efficacy of immune response.

Evaluation of the pollution and human health risks posed by heavy metals in the atmospheric dust in Ebinur Basin in Northwest China.

Recently, a large amount of research assessing pollution levels and the related health risks posed by atmosphere dust has been undertaken worldwide. However, little work has been done in the oases of the arid regions of Northwest China. In this paper, we studied the pollution and health risks over a year of seven heavy metals in the atmospheric dust of Ebinur Basin, a typical oasis in Northwest China. The results showed the following: (1) The annual amount of atmospheric deposition in Ebinur Basin was 298.23 g m(-2) and the average monthly atmospheric deposition was 25.06 g m(-2). The average and maximum values of the seven heavy metals measured were all below the National Soil Environmental Quality Standards (2nd). (2) Heavy metals of Cu, Cr, and As in the atmospheric deposition mainly originated from the natural geological background, while Zn came from human activity. This study also showed that among the seven measured heavy metals, the ratios of the no-pollution status of Pb, Cd, and Hg were higher than those of others with moderate degrees of pollution also accounting for a certain ratio. (3) The carcinogenic risks from As, Cd, and Cr were all lower than the corresponding standard limit values, and these metals are considered not harmful to the health of the basin. However, there is a relatively high risk of exposure for children from hand-to-mouth intake, which is worthy of attention. This research showed that both human activity and natural factors, such as wind and altitude, influenced the heavy metal contents in the atmospheric dust of the study area. Furthermore, recent human activity in the study area had the most negative influence on the accumulation of the heavy metals and the corresponding health risks, especially for Hg, Pb, and Cd, which is worthy of attention.

The disastrous effects of salt dust deposition on cotton leaf photosynthesis and the cell physiological properties in the Ebinur Basin in Northwest China.

Salt dust in rump lake areas in arid regions has long been considered an extreme stressor for both native plants and crops. In recent years, research on the harmful effects of salt dust on native plants has been published by many scholars, but the effect on crops has been little studied. In this work, in order to determine the impact of salt dust storms on cotton, we simulated salt dust exposure of cotton leaves in Ebinur Basin in Northwest China, and measured the particle sizes and salt ions in the dust, and the photosynthesis, the structure and the cell physiological properties of the cotton leaves. (1) Analysis found that the salt ions and particle sizes in the salt dust used in the experiments were consistent with the natural salt dust and modeled the salt dust deposition on cotton leaves in this region. (2) The main salt cations on the surface and inside the cotton leaves were Na+, Ca2+, Cl- and SO42-, while the amounts of CO3- and HCO3- were low. From the analysis, we can order the quantity of the salt cations and anions ions present on the surface and inside the cotton leaves as Na+>Ca2+>Mg2+>K+ and Cl->SO42->HCO3->CO3-, respectively. Furthermore, the five salt dust treatment groups in terms of the total salt ions on both the surface and inside the cotton leaves were A(500g.m-2)>B(400g.m-2)>C(300g.m-2)>D(200g.m-2)>E(100g.m-2)>F(0g.m-2). (3)The salt dust that landed on the surface of the cotton leaves can significantly influence the photosynthetic traits of Pn, PE, Ci, Ti, Gs, Tr, WUE, Ls, φ, Amax, k and Rady of the cotton leaves. (4)Salt dust can significantly damage the physiological functions of the cotton leaves, resulting in a decrease in leaf chlorophyll and carotenoid content, and increasing cytoplasmic membrane permeability and malondialdehyde (MDA) content by increasing the soluble sugar and proline to adjust for the loss of the cell cytosol. This increases the activity of antioxidant enzymes to eliminate harmful materials, such as the intracellular reactive oxygen and MDA, thus reducing the damage caused by the salt dust and maintaining normal physiological functioning. Overall, this work found that the salt dust deposition was a problem for the crop and the salt dust could significantly influence the physiological and biochemical processes of the cotton leaves. This will eventually damage the leaves and reduce the cotton production, leading to agricultural economic loss. Therefore, attention should be paid to salt dust storms in the Ebinur Basin and efficient measures should be undertaken to protect the environment.

Heavy metal contamination, sources, and pollution assessment of surface water in the Tianshan Mountains of China.

In order to gain insight into heavy metal contamination occurring in the surface water of the Tianshan Mountains in northwest China, we collected surface water samples from there, tested heavy metals Pb, Ni, Cd, Co, Hg, As, Cu, Mn, Zn, and Cr, and then we analyzed the data using typical analysis, multivariate statistical, and pollution index methods. Results showed that (1) the order of the average values of the ten kinds of heavy metals in all the water samples was as follows: Zn > Mn > Cu > Co > Ni > Pb > Cr > As > Hg > Cd. The maximum variation coefficients of Zn and Pb were 138.96 and 145.86 %, respectively, indicating that these heavy metal concentrations varied largely between different sampling locations. (2) Research showed the average concentrations of Pb, Cd, As, Cu, Zn, and Cr were all within the national surface water standard of class IV and those of As, Cu, Mn, and Cr were all within the range of the Drinking Water Guidelines from the WHO, indicating the surface water of the Tianshan Mountains is clean. (3) Multivariate statistical analysis showed that Cu, Cd, Mn, Hg, Zn, and Pb have close correlations, and they mainly came from artificial sources; while Ni, As, Co, Cu, and Cr mainly came from natural sources. The results of correlation analysis, principal component analysis, and cluster analysis are consistent. (4) Pollution evaluation showed the values of comprehensive pollution index (WQI) of ten kinds of heavy metals in three sections were all lower than 2, suggesting the low levels of pollution, while the over-limit ratios of Pb and Zn in water samples of the middle Urumqi-Akesu section, As in the western Zhaosu-Tekesi section, and Pb, Hg, and Zn in the eastern Balikun-Yiwu section were all above 10 %. This research shows that recent economic development of the Tianshan Mountains has negatively influenced the heavy metal concentrations in the surface water, although the concentrations of the ten kinds of tested heavy metals are relatively low.

The occurrence, sources and spatial characteristics of soil salt and assessment of soil salinization risk in Yanqi basin, northwest China.

In order to evaluate the soil salinization risk of the oases in arid land of northwest China, we chose a typical oasis-the Yanqi basin as the research area. Then, we collected soil samples from the area and made comprehensive assessment for soil salinization risk in this area. The result showed that: (1) In all soil samples, high variation was found for the amount of Ca2+ and K+, while the other soil salt properties had moderate levels of variation. (2) The land use types and the soil parent material had a significant influence on the amount of salt ions within the soil. (3) Principle component (PC) analysis determined that all the salt ion values, potential of hydrogen (pHs) and ECs fell into four PCs. Among them, PC1 (C1-, Na+, SO4(2-), EC, and pH) and PC2 (Ca2+, K+, Mg2+and total amount of salts) are considered to be mainly influenced by artificial sources, while PC3 and PC4 (CO3(-) and HCO3(2-)) are mainly influenced by natural sources. (4) From a geo-statistical point of view, it was ascertained that the pH and soil salt ions, such as Ca2+, Mg2+ and HCO3(-), had a strong spatial dependency. Meanwhile, Na+ and Cl- had only a weak spatial dependency in the soil. (5) Soil salinization indicators suggested that the entire area had a low risk of soil salinization, where the risk was mainly due to anthropogenic activities and climate variation. This study can be considered an early warning of soil salinization and alkalization in the Yanqi basin. It can also provide a reference for environmental protection policies and rational utilization of land resources in the arid region of Xinjiang, northwest China, as well as for other oases of arid regions in the world.

Establishment and Application of Methods for Detecting H5N1 Pathogen with Multiple Probe RT-PCR / 现代检验医学杂志

Objective To establish and apply the multiple probe RT-PCR analysis for H5N1 pathogen detection methods. Methods Used the gene sequences published in GenBank,which were designed and synthesized two pairs of specific primers (P1/P2,P3/P4)accorded the conserved regions.Through the optimization of amplification conditions to establish the rapid detection of two viruses duplex PCR method.Results The suitable primer concentration:P1/P2 was 0.32μmol/L,P3/P4 was 0.96μmol/L.The amount of the minimum virus nucleic acid was 2 ng/μl by the double detect,H5N1 pathogen mixed were occurred specific bands in the corresponding location,and other viruses and blank control strips had not bands.Conclu-sion A variety of probes for RT-PCR analysis H5N1 pathogen detection methods in a reasonable application of primer con-centration under has good sensitivity and specificity,and it is worth the inspection application.

The drug resistance of Escherichia coli isolated from urinary tract infection and risk factors of quinolone resistance strains / 中国医师进修杂志

Objective To analyze the drug resistance of Escherichia coli isolated from urinary tract infection and risk factors of quinolone resistance strains.Methods A total of 705 cases (strains) with Escherichia coli drug resistance isolated from urine specimens were divided into quinolone sensitive group [474 cases(strains)] and quinolone resistance group [231 cases(strains)].The risk factors of the quinolone resistance strains were analyzed.Results The sensitivity rate of amoxicillin/clavulanic acid,cefalotin,ceftazidime,aztreonam,piperacillin,amikacin,compound sulfamethoxazole,ciprofloxacin,gentamicin,levofloxacin,cefepime in quinolone resistance group was higher than that in quinolone sensitive group [50.2％(238/474) vs.78.8％(182/231),11.6％(55/474) vs.48.5％(112/231),17.9％(85/474) vs.63.2％(146/231),15.0％(71/474) vs.57.6％(133/231),3.2％(15/474) vs.27.7％(64/231),80.8％(383/474)vs.93.1％(215/231),16.0％(76/474) vs.49.8％(115/231),0 vs.100.0％(231/231),32.5％ (154/474)vs.70.6％ (163/231),3.8％ (18/474) vs.98.7％ (228/231),18.6％ (88/474) vs.63.2％ (146/231),P ＜0.05].Logistic regression analysis showed history of using the third generation cephalosporins and quinolones,urinary drainage and bacterium producing extra-broad spectrum beta-lactamase was independent risk factor for quinolone resistance Escherichia coli (P ＜ 0.05).Conclusions The epidemic of quinolone resistance Escherichia coli isolated from urine specimens is extremely serious.The quinolone resistance is strong,and infection patients have a high medical cost and average length of stay.The quinolone resistance Escherichia coli infection has multiple independent risk factors.To strengthen the control of the independent risk factors can effectively prevent quinolone resistance strains infection spread.