67 research outputs found
Pyrolyzing soft template-containing poly(ionic liquid) into hierarchical N-doped porous carbon for electroreduction of carbon dioxide
Heteroatom-doped carbon materials have demonstrated great potential in the electrochemical reduction reaction of CO2 (CO2RR) due to their versatile structure and function. However, rational structure control remains one challenge. In this work, we reported a unique carbon precursor of soft template-containing porous poly(ionic liquid) (PIL) that was directly synthesized via free-radical self-polymerization of ionic liquid monomer in a soft template route. Variation of the carbonization temperature in a direct pyrolysis process without any additive yielded a series of carbon materials with facile adjustable textural properties and N species. Significantly, the integration of soft-template in the PIL precursor led to the formation of hierarchical porous carbon material with a higher surface area and larger pore size than that from the template-free precursor. In CO2RR to CO, the champion catalyst gave a Faraday efficiency of 83.0% and a current density of 1.79 mA?cm?2 at ?0.9 V vs. reversible hydrogen electrode (vs. RHE). The abundant graphite N species and hierarchical pore structure, especially the unique hierarchical small-/ultra-micropores were revealed to enable better CO2RR performance
Resilient smart power grid synchronization estimation method for system resilience with partial missing measurements
With the increasing demand for power system stability and resilience, effective real-time tracking plays a crucial role in smart grid synchronization. However, most studies have focused on measurement noise, while they seldom think about the problem of measurement data loss in smart power grid synchronization. To solve this problem, a resilient fault-tolerant extended Kalman filter (RFTEKF) is proposed to track voltage amplitude, voltage phase angle and frequency dynamically. First, a three-phase unbalanced network's positive sequence fast estimation model is established. Then, the loss phenomenon of measurements occurs randomly, and the randomness of data loss's randomness is defined by discrete interval distribution [0], [1]. Subsequently, a resilient fault-tolerant extended Kalman filter based on the real-time estimation framework is designed using the time-stamp technique to acquire partial data loss information. Finally, extensive simulation results manifest the proposed RFTEKF can synchronize the smart grid more effectively than the traditional extended Kalman filter (EKF)
Determination of banned pigment quinoline yellow in pastries by salting out assisted-high performance liquid chromatography
ObjectiveTo develop an analytical method for fast determination of banned pigment quinoline yellow in pastries by salting out assisted-high performance liquid chromatography.MethodsThe sample was extracted with 40% methanol-sodium chloride-water, precipitated with potassium ferrocyanide-zinc acetate solution, eluted with mobile phase of methanol-0.02 mol/L ammonium acetate solution, separated by X-Bridge C18 column v(150 mm×4.6 mm, 3.5 μm), and detected with diode -array detector by external standard method.ResultsThe method showed good linearity (r>0.999) in the range of 0.4-40.0 μg/mL. The limit of detection (S/N=3) was 1.25 mg/kg and the limit of quantification (S/N=10) was 5.0 mg/kg. The average recoveries of three different concentrations level at 5.0, 10.0 and 50.0 mg/kg ranged from 89.18% to 110.10%, with relative standard deviation in the range of 2.83%-8.65%.ConclusionThe method was convenient, accurate and reproducible, and it was suitable for qualitative and quantitative analysis of banned pigment quinoline yellow in pastries
Hepatitis C Virus Infection, Linxian, China1
The prevalence of HCV infection was high among older citizens of Linxian, China, in 2000
IκBα polymorphism at promoter region (rs2233408) influences the susceptibility of gastric cancer in Chinese
<p>Abstract</p> <p>Background</p> <p>Nuclear factor of kappa B inhibitor alpha (IκBα) protein is implicated in regulating a variety of cellular process from inflammation to tumorigenesis. The objective of this study was to investigate the susceptibility of rs2233408 T/C genotype in the promoter region of <it>IκBα </it>to gastric cancer and the association of this polymorphism with clinicopathologic variables in gastric cancer patients.</p> <p>Methods</p> <p>A population-based case-control study was conducted between 1999 and 2006 in Guangdong Province, China. A total of 564 gastric cancer patients and 566 healthy controls were enrolled in this study. rs2233408 genotypes in <it>IκBα </it>were analyzed by TaqMan SNP genotyping assay.</p> <p>Results</p> <p>Both rs2233408 T homozygote (TT) and T heterozygotes (TC and TT) had significantly reduced gastric cancer risk (TT: OR = 0.250, 95% CI = 0.069-0.909, <it>P </it>= 0.035; TC and TT: OR = 0.721, 95% CI = 0.530-0.981, <it>P </it>= 0.037), compared with rs2233408 C homozygote (CC). rs2233408 T heterozygotes were significantly associated with reduced risk of intestinal-type gastric cancer with ORs of 0.648 (95% CI = 0.459-0.916, <it>P </it>= 0.014), but not with the diffuse or mix type of gastric cancer. The association between rs2233408 T heterozygotes and gastric cancer appeared more apparent in the older patients (age>40) (OR = 0.674, 95% CI = 0.484-0.939, <it>P </it>= 0.02). rs2233408 T heterozygotes was associated with non-cardiac gastric cancer (OR = 0.594, 95% CI = 0.411-0.859, <it>P </it>= 0.006), but not with cardiac gastric cancer. However, rs2233408 polymorphism was not associated with the prognosis of gastric cancer patients.</p> <p>Conclusions</p> <p><it>IκBα </it>rs2233408 T heterozygotes were associated with reduced risk of gastric cancer, especially for the development of certain subtypes of gastric cancer in Chinese population.</p
Calculation of seasonal agricultural grey water footprint in monsoon region based on river reference conditions
Grey water footprint accounting is of great significance to water resources management. The two important parameters of grey water footprint accounting, the natural background concentration of pollutants and the pollutant export coefficient, have obvious seasonal differences in the monsoon region, while the possible seasonal differences of grey water footprint in the monsoon region had been less considered in the previous research of grey water footprint accounting. This paper calculated the seasonal agricultural grey water footprint of Zhangjiakou City in North China by taking the river reference condition of total phosphorus as its natural background concentration and considering the seasonal difference of river reference condition of total phosphorus and the pollutant export coefficient. The results showed that the agricultural grey water footprint calculated with the reference condition of total phosphorus as the natural background concentration were 1.60 and 1.38 times of that calculated with zero as the natural background concentration in the rainy season and dry season, respectively. Due to the seasonal difference in the proportion of pollutants entering the river and the reference condition of total phosphorus, the agricultural grey water footprint showed obvious seasonal differences. The agricultural grey water footprint in rainy season was 11.73 times higher than that in dry season. In the composition of agricultural grey water footprint in Zhangjiakou from 2003 to 2018, the grey water footprint of livestock and poultry accounted for a large proportion. Districts and counties with relatively large agricultural grey water footprint in Zhangjiakou were concentrated in the south and north of Zhangjiakou, mainly including Zhuolu, Huailai, Yuxian, Xuanhua and Zhangbei; The districts and counties with relatively small agricultural grey water footprint were mainly located in the urban area of Zhangjiakou, including Qiaodong District, Qiaoxi District and Xiahuayuan District. This paper could clarify the seasonal difference of agricultural grey water footprint accounting in monsoon region and promote the development of grey water footprint accounting methods
Real-Time Analysis and Forecasting of Multisite River Flow Using a Distributed Hydrological Model
A spatial distributed hydrological forecasting system was developed to promote the analysis of river flow dynamic state in a large basin. The research presented the real-time analysis and forecasting of multisite river flow in the Nakdong River Basin using a distributed hydrological model with radar rainfall forecast data. A real-time calibration algorithm of hydrological distributed model was proposed to investigate the particular relationship between the water storage and basin discharge. Demonstrate the approach of simulating multisite river flow using a distributed hydrological model couple with real-time calibration and forecasting of multisite river flow with radar rainfall forecasts data. The hydrographs and results exhibit that calibrated flow simulations are very approximate to the flow observation at all sites and the accuracy of forecasting flow is gradually decreased with lead times extending from 1 hr to 3 hrs. The flow forecasts are lower than the flow observation which is likely caused by the low estimation of radar rainfall forecasts. The research has well demonstrated that the distributed hydrological model is readily applicable for multisite real-time river flow analysis and forecasting in a large basin
Evaluation of Technology for the Analysis and Forecasting of Precipitation Using Cyclostationary EOF and Regression Method
Precipitation time series exhibit complex fluctuations and statistical changes. Existing research stops short of a simple and feasible model for precipitation forecasting. In this article, the authors investigate and forecast precipitation variations in South Korea from 1973 to 2021 using cyclostationary empirical orthogonal function (CSEOF) and regression methods. First, empirical orthogonal function (EOF) and CSEOF analyses are used to examine the periodic changes in the precipitation data. Then, the autoregressive integrated moving average (ARIMA) method is applied to the principal component (PC) time series derived from the EOF and CSEOF precipitation analyses. The fifteen leading EOF and CSEOF modes and their corresponding PC time series clearly reflect the spatial distribution and temporal evolution characteristics of the precipitation data. Based on the PC forecasts of the EOF and CSEOF models, the EOF–ARIMA composite model and CSEOF–ARIMA composite model are used to obtain quantitative precipitation forecasts. The comparison results show that both composite models have good performance and similar accuracy. However, the performance of the CSEOF–ARIMA model is better than that of the EOF–ARIMA model under various measurements. Therefore, the CSEOF–ARIMA composite forecast model can be considered an efficient and feasible technology representing an analytical approach for precipitation forecasting in South Korea
Structural Studies of Bypass of Forespore Protein C from Bacillus Subtilis to Reveal Its Inhibitory Molecular Mechanism for SpoIVB
Activation of pro-σK processing requires a signaling protease SpoIVB that is secreted from the forespore into the space between the two cells during sporulation in Bacillus subtilis. Bypass of forespore protein C (BofC) is an inhibitor preventing the autoproteolysis of SpoIVB, ensuring the factor σK operates regularly at the correct time during the sporulation. However, the regulatory mechanisms of BofC on pro-σK processing are still unclear, especially in the aspect of the interaction between BofC and SpoIVB. Herein, the recombinant BofC (rBofC) was expressed in the periplasm by the E. coli expression system, and crystal growth conditions were obtained and optimized. Further, the crystal structure of rBofC was determined by X-ray crystallography, which is nearly identical to the structures determined by NMR and predicted by AlphaFold. In addition, the modeled structure of the BofC–SpoIVB complex provides insights into the molecular mechanism by which domain 1 of BofC occupies the active site of the SpoIVB serine protease domain, leading to the inhibition of the catalytical activity of SpoIVB and prevention of the substrate of SpoIVB (SpoIVFA) from binding to the active site
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