The oil and gas (O&G) sector represents a large source of greenhouse gas (GHG) emissions globally. However, estimates of O&G emissions rely upon bottom-up approaches, and are rarely evaluated through atmospheric measurements. Here, we use aircraft measurements over the Canadian oil sands (OS) to derive the first top-down, measurement-based determination of the their annual CO2 emissions and intensities. The results indicate that CO2 emission intensities for OS facilities are 13-123% larger than those estimated using publically available data. This leads to 64% higher annual GHG emissions from surface mining operations, and 30% higher overall OS GHG emissions (17 Mt) compared to that reported by industry, despite emissions reporting which uses the most up to date and recommended bottom-up approaches. Given the similarity in bottom-up reporting methods across the entire O&G sector, these results suggest that O&G CO2 emissions inventory data may be more uncertain than previously considered.
Aiming at the requirement of miniaturization and high performance of antenna unit in
MMW portable imaging system, a novel approach is presented to decrease the side lobe for
millimeter wave applications using metamaterial (MTM) profile based antennas. The extraction of
effective parameters of a metamaterial unit cell and its effect are also presented. The simulation
results show that the side lobe of the proposed antenna is lower than -17dB at 35GHz.
Microplastics, as an emerging pollutant of global importance, have been well documented in aquatic ecosystems. However, little is known about the effects of microplastics on agroecosystems, particularly for soil microbial com- munities. Herein, microplastics collected from cotton fields in Xinjiang, China, were analysed with a scanning electron microscope (SEM) and high-throughput sequencing to investigate the attached bacterial communities. Microplastic surfaces, especially pits and flakes, were colonized by various microorganisms, suggesting active hy- drolysis of plastic debris. The bacterial communities colonizing microplastics were significantly different in struc- ture from those in the surrounding soil, plant litter and macroplastics. In addition, statistical analysis of differentially abundant OTUs showed that microplastics serve as a “special microbial accumulator” in farmland soil, enriching some taxa that degrade polyethylene, such as Actinobacteria, Bacteroidetes and Proteobacteria. Co-occurrence network analysis revealed that the biotic interactions between microorganisms on microplastics are as complex as those in soil, and Acidobacteria, Chloroflexi, Gemmatimonadetes, and Bacteroidetes are consid- ered keystone species in bacterial communities. Collectively, the findings imply that microplastics acted as a dis- tinct habitat for bacteria in farmland soil, which increases our understanding of microplastic pollution. 
The rapid aggregation/sedimentation and decreased transport of nanoscale zero-valent iron (nZVI) particles limit their application in groundwater remediation. To decrease the aggregation/sedimentation and increase the transport of nZVI, sodium alginate (a natural polysaccharide) and bentonite (one type of ubiquitous clay) were employed to modify nZVI. Different techniques were utilized to characterize the modified nZVI. We found that modification with either sodium alginate or bentonite could disperse nZVI and shifted their zeta potentials from positive to negative. Comparing with the bare nZVI, the sedimentation rates of modified nZVI either by sodium alginate or bentonite are greatly decreased and their transport are significantly increased. The transport of modified nZVI can be greatly increased by increasing flow rate. Furthermore, Cr(VI) can be efficiently removed by the modified nZVI (both sodium alginate and bentonite modified nZVI). Comparing with bare nZVI, the two types of modified nZVI contain lower toxicities to Escherichia coli. The results of this study indicate that both sodium alginate and bentonite can be employed as potential stabilizers to disperse nZVI and improve their application feasibility for in situ groundwater remediation.
The hepatitis B surface antigen (HBsAg) is a vital serum marker for hepatitis B virus (HBV) infection. Amino acid (AA) substitutions in small hepatitis B surface protein (SHBs) are known to affect HBsAg level. However, how the genetic backbones of SHBs sequences would affect the roles of a specific AA substitution on HBsAg level remains unclear. In this study, we found that sI126 had a very high substitution detection rate of 17.54% (40/228) in untreated chronic hepatitis B cohort with subgenotype C2 HBV infection. Among different substitution types at sI126, the sI126T (N = 28) was found to be associated with significantly lower serum HBsAg level. Clone sequencing revealed that sI126T-harboring SHBs sequences had varied genetic backbones with zero to nine additional AA substitutions. Thus, we constructed 24 HBsAg expression plasmids harboring sI126T without (plasmid 1, P1) or with (P2-P24) additional AA substitution(s) and studied them in the HepG2 cells. The HBsAg levels were determined by both ELISA and Western blot. In vitro experiments showed that P1 significantly reduced HBsAg level and its secretion (p < .05), however, P2-P24 showed various extracellular and intracellular HBsAg levels. No significant differences were detected among the HBsAg mRNA levels of nine representative mutant plasmids. Our findings suggest that the modulation of HBsAg level by sI126T is affected by additional AA substitution(s) in the S region of HBV. The effects of AA combination substitutions in SHBs sequences on HBsAg levels are worthwhile for more attentions in terms of HBV biology and its clinical application.
Keywords: Amino acid substitution; Genetic backbone; Hepatitis B surface antigen; Secretion;
Background: Diatoms are of great significance to primary productivity in oceans, yet little is known about their biogeographic distribution in oligotrophic rivers. Results: With the help of metabarcoding analysis of 279 samples from the Yangtze River, we provided the first integral biogeographic pattern of planktonic and benthic diatoms over a 6030 km continuum along the world's third largest river. Our study revealed spatial dissimilarity of diatoms under varying landforms, including plateau, mountain, foothill, basin, foothill-mountain, and plain regions, from the river source to the estuary. Environmental drivers of diatom communities were interpreted in terms of photosynthetically active radiation, temperature, channel slope and nutrients, and human interference. Typical benthic diatoms, such as Pinnularia, Paralia, and Aulacoseira, experienced considerable reduction in relative abundance downstream of the Three Gorges Dam and the Xiluodu Dam, two of the world's largest dams. Conclusions: Our study revealed that benthic diatoms are of particular significance in characterizing motile guild in riverine environments, which provides insights into diatom biogeography and biogeochemical cycles in large river ecosystems.
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.