Geochronology is essential for understanding Earth's history. The availability of precise and accurate isotopic data is increasing; hence it is crucial to develop transparent and accessible data reduction techniques and tools to transform raw mass spectrometry data into robust chronological data. Here we present a Monte Carlo sampling approach to fully propagate uncertainties from linear regressions for isochron dating. Our new approach makes no prior assumption about the causes of variability in the derived chronological results and propagates uncertainties from both experimental measurements (analytical uncertainties) and underlying assumptions (model uncertainties) into the final age determination. Using synthetic examples, we find that although the estimates of the slope and y-intercept (hence age and initial isotopic ratios) are comparable between the Monte Carlo method and the benchmark ``Isoplot" algorithm, uncertainties from the later could be underestimated by up to 60%, which are likely due to an incomplete propagation of model uncertainties. An additional advantage of the new method is its ability to integrate with geological information to yield refined chronological constraints. The new method presented here is specifically designed to fully propagate errors in geochronological applications involves linear regressions such as Rb-Sr, Sm-Nd, Re-Os, Pt-Os, Lu-Hf, U-Pb (with discordant points), Pb-Pb and Ar-Ar. (C) 2018 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.
OBJECTIVES: The evolution of multimorbidity describes the continuum from a healthy status to the development of a single disease and further progression to multimorbidity with additional diseases. We investigated the evolution of cardiometabolic multimorbidity and risk for mortality in a Chinese population. DESIGN: Longitudinal cohort study using data from the CHinese Electronic health Records Research in Yinzhou (CHERRY) study, with 5.43 million person-years follow-up (median 5.16 years). PARTICIPANTS: Data for 1 038 704 adults (total 22 750 deaths) were analysed. EXPOSURE: Cardiometabolic multimorbidity was defined as ever being diagnosed with two or more of three diseases: hypertension, diabetes and cardiovascular disease (CVD). PRIMARY AND SECONDARY OUTCOME MEASURES: Age-adjusted and sex-adjusted HRs were calculated for all-cause mortality. RESULTS: The cardiometabolic disease status of 105 209 (10.1%) individuals changed during the follow-up. The prevalence of cardiometabolic multimorbidity increased from 2.41% (95% CI: 2.38% to 2.44%) to 5.94% (95% CI: 5.90% to 5.99%). Baseline multimorbidity status showed the HR (95% CI) was 1.37 (1.33 to 1.42) in those with one disease, 1.71 (1.64 to 1.79) in those with two diseases and 2.22 (2.00 to 2.46) in those with three diseases. The highest HRs were observed for CVD only (3.31, 95% CI: 3.05 to 3.59) or diabetes and CVD (3.12, 95% CI: 2.37 to 4.11). Those with hypertension only had the lowest HR (1.26, 95% CI: 1.22 to 1.30). Longitudinal data showed the HRs (95% CI) in patients with one, two and three diseases were 1.36 (1.32 to 1.41), 2.03 (1.96 to 2.10) and 2.16 (2.05 to 2.29), respectively. CONCLUSIONS: The prevalence of cardiometabolic multimorbidity in a general Chinese population increased more than doubled over 5 years, indicating rapid evolution of cardiometabolic multimorbidity. A history of CVD dominates the risk for mortality. A complementary strategy for primary and secondary prevention of cardiometabolic diseases is needed in China.
Nitrous oxide (N2O) and nitric oxide (NO) emissions from domestic wastewater treatment had been widely investigated due to their severe greenhouse effect and stratospheric ozone depletion. Researches concerning N2O and NO emissions from industrial wastewater treatment which usually contain high concentrations of nitrogen and refractory organics were still limited. In this study, N2O and NO emissions from a biological aerated filter (BAF) for coking wastewater treatment were investigated that achieved efficient nitrogen and chemical oxygen demand (COD) removal efficiency through short-cut nitrification and denitrification. Notably, emission factor of N2O and NO reached 23.58% and 0.09% respectively, much higher than those emitted from most domestic wastewater treatment plants. Moreover, batch experiments revealed that nitrifier denitrification contributed as high as 97.17% and 93.89% of the total generated N2O and NO, which was supposed to be the main source of green-house gases (GHGs) during coking wastewater treatment. The inhibition of denitrifying reductase by the toxic components in coking wastewater and the severe nitrite accumulations were key factors promoting the high emission of N2O and NO. Microbial community analysis based on high throughput sequencing of 16S rRNA gene revealed that ammonia-oxidizing bacteria and denitrifying bacteria distributed abundantly in the BAF reactor, while nitrite-oxidizing bacteria was almost absent. The huge imbalance between NO and N2O reductase was an underlying explanation for the high N2O emission in the present coking wastewater treatment according to Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) result. This study is of great significance to understanding the high N2O and NO emission and developing the control strategy when treating industrial wastewater with high-strength nitrogen and refractory organics.
The principle of ion concentration polarization (ICP) is the most efficient method for achieving nano-electrokinetic ion enrichment. In this paper, nano-electrokinetic ion enrichment of highly viscosity fluids in micronanochannel was investigated. Based on the Poisson-Nernst--Plank (PNP) equations coupled with the Navier-Stokes equation, ion enrichment and enrichment breakdown, the effects of the width and wall structure of the nanochannel on the ion enrichment were investigated. It is concluded that the ion enrichment is attributed to the balance between the electrophoresis effect provided by the applied voltage and the repulsive force generated by the surface charge. The ion enrichment is divided into three stages: enrichment generation, enrichment promotion and enrichment breakdown. When the applied voltage increases, the ion concentration first increases. When the voltage reaches the peak, it gradually decreases. At the same voltage, both the peak concentration and the peak voltage increase as the width of the nanochannel decreases. The nanochannel of the square wave wall structure has highest peak concentration than the zigzag type, the multi-wave type and the straight line type. This work provides a significant theoretical basis for increasing enrichment ratio and ion concentration in low concentration molecular detection tasks.
In order to analyze and compare the differences in pore structures between shale gas and shale oil formations, a few samples from the Longmaxi and Bakken Formations were collected and studied using X-ray diffraction, LECO TOC measurement, gas adsorption and field-emission scanning electron microscope. The results show that samples from the Bakken Formation have a higher TOC than those from the Longmaxi Formation. The Longmaxi Formation has higher micropore volume and larger micropore surface area and exhibited a smaller average distribution of microsize pores compared to the Bakken Formation. Both formations have similar meso-macropore volume. The Longmaxi Formation has a much larger meso-macropore surface area, which is corresponding to a smaller average meso-macropore size. CO2 adsorption data processing shows that the pore size of the majority of the micropores in the samples from the Longmaxi Formation is less than 1 nm, while the pore size of the most of the micropores in the samples from the Bakken Formation is larger than 1 nm. Both formations have the same number of pore clusters in the 2–20 nm range, but the Bakken Formation has two additional pore size groups with mean pore size diameters larger than 20 nm. Multifractal analysis of pore size distribution curves that was derived from gas adsorption indicates that the samples from the Longmaxi Formation have more significant micropore heterogeneity and less meso-macropore heterogeneity. Abundant micropores as well as meso-macropores exist in the organic matter in the Longmaxi Formation, while the organic matter of the Bakken Formation hosts mainly micropores.
In this paper, two new nanoscale-extended attractive (alpha) functions in Soave and exponential types are developed for the first time, which are applied and evaluated for the calculations of the thermodynamic and phase properties of confined fluids coupled with a modified equation of state (EOS). Moreover, a novel method is proposed and verified to determine the nanoscale acentric factors. The behaviour of several important parameters, i.e., minimum reduced temperature, nanoscale acentric factor, alpha function and its first and second derivatives, are specifically analyzed at different temperatures and pore radii. The newly-developed alpha functions are validated to accurately calculate the thermodynamic and phase properties in bulk phase (rp = 1000 nm) and nanopores. The minimum reduced temperature from the Soave alpha function occurs at the acentric factor of ω = −0.295211 while the exponential function is monotonically related to the temperatures without any minimum conditions. Moreover, the acentric factors and intermolecular attractivities are found to be increased with the pore radius reductions at most temperatures, wherein they remain constant or slightly increase by reducing the pore radius at rp ≥ 50 nm while become quickly increased at rp < 50 nm. It should be noted that the alpha functions are decreased with the pore radius reduction at the critical temperature (Tr = 1). The intermolecular attractivities are found to be stronger for the heavier or high carbon number components. Furthermore, the first and second derivatives of the Soave and exponential alpha functions to the temperatures are continuous at T ≤ 4000 K. Overall, the two original (Soave and exponential) and two nanoscale-extended alpha functions are proven to be accurate for the thermodynamic and phase calculations in bulk phase and nanopores.
Evidence suggesting an association between ozone exposure and stroke risk remains inconsistent; variations in the distributions of susceptibilities of the study populations may explain some of it. We examined the hypothesis in a general Chinese population. During 2013–2015, 1356 first-ever stroke events were selected from a large representative sample, the China National Stroke Screening Survey (CNSSS) database; daily maximal 8-hour ozone concentrations were obtained from spatiotemporally interpolated estimates of in-situ observations over China. We conducted a time-stratified case-crossover design to assess associations between stroke risk and ambient ozone exposure. Next, potential effect modifiers were identified using interaction analyses. Final, a well-established approach was applied to estimate individual-level susceptibility (i.e., the individual-specific effect given a certain combination of multiple effect-modifiers) and its probability distribution among all the CNSSS participants (n = 1,292,010). With adjustments for temperature, relative humidity and ambient fine particulate matter exposure, a 10-μg/m3 increment in mean ozone levels 2–3 day prior to symptom onset was associated with a 3.0% change in stroke risk (95% confidence interval: −1.2%, 7.3%). This association was statistically significantly enhanced by male gender, rural residence and low vegetable and fruit consumption. The subgroup results suggested that a fraction of the population might be considerably affected by ozone, regardless of the insignificant association in average level. The analysis of susceptibility distribution further indicated that the ozone-stroke association was statistically significantly positive in 14% of the general population. Susceptibility to ozone-related stroke significantly varied among Chinese adults. Characterizing individual-level susceptibility reveals the complexity underlying the weak average effect of ozone, and supports to plan subpopulation-specific interventions to mitigate the stroke risk.
Mutations in hepatitis B virus (HBV) surface promoter II (SPII) have not been well studied in hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) patients. We aimed to investigate SPII mutations in such patients and their biological and clinical impacts. Direct sequencing was used to detect SPII mutations in 106 HBeAg-positive treatment-naïve CHB patients with genotype C (82.1% (87/106) was C2) HBV infection. Results showed that mutation frequency in transcription factor (TF) unbinding region was significantly higher than that in TF binding region of SPII (C1: 3.4% vs. 1.3%; C2: 2.6% vs. 1.3%; p < 0.0001). Luciferase assay revealed distinct promoter activities among SPII mutants; especially SPII of G120A mutant had a 15-fold higher activity than that of wild-type (p < 0.001). In vitro experiments in HepG2 cells showed that G82A, A115C and G120A mutants increased the hepatitis B surface antigen (HBsAg) levels, while C18T had an opposite effect. G82A, A115C and G120A mutants boosted the intracellular HBV total RNA level. G120A mutation resulted in an increased HBV DNA level in vitro, consistent with the serological results in patients. Thus, novel SPII mutations would affect promoter activity, HBsAg, HBV DNA and HBV total RNA levels, suggesting their potential biological and clinical significances.
Keywords: C genotype; HBeAg-positive; HBsAg; hepatitis B virus; mutation; surface promoter.
With the development of droplet microfluidic technology, there are some problems in the current generation of droplets using microchannels, such as high cost, and difficulty in controlling the size of droplets and the generation frequency. This paper applies numerical simulation method to study T-junction microchannels. Studies have shown that the pressure difference in the T-junction microchannel and the viscous shear force of the continuous phase act as a driving force in the droplet formation process. The effective droplet diameter decreases as the Ca increases, and the generation frequency increases as Ca increases. Based on the level-set method, three T-junction microchannels with step structure at different positions are designed to study the problem of generating monodisperse high-throughput microdroplets. This paper achieves flexible control of droplet generation using three different designs. In the three designs, when the step position is in the middle, the generated droplet diameter is the smallest and the frequency is the fastest. Therefore, studies have shown that the step structure in the middle is the optimal solution for generating monodisperse high-throughput microdroplets.