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Heteroatom-doped carbon nanotubes are considered as promising materials for supercapacitors because of their prominent contributions in terms of faradaic capacitance and electron donor capability.

Accurate event identification is an essential part of situation awareness ability for power system operators. Therefore, this work proposes an integrated event identification algorithm for power systems. First, to obtain and filter suitable inputs for event identification, an event detection trigger based on the rate of change of frequency (RoCoF) is presented. Then, the wave arrival time difference-based triangulation method considering the anisotropy of wave propagation speed is utilized to estimate the location of the detected event. Next, the two-dimensional orthogonal locality preserving projection (2D-OLPP)-based method, which is suitable for multiple types of measured data, is employed to achieve higher effectiveness in extracting the event features compared with traditional one-dimensional projection and principle component analysis (PCA). Finally, the random undersampling boosted (RUSBoosted) trees-based classifier, which can mitigate the data sample imbalance issue, is utilized to identify the type of the detected event. The proposed approach is demonstrated using the actual measurement data of U.S. power systems from FNET/GridEye. Comparison results show that the proposed event identification algorithm can achieve better performance than existing approaches.

Fibrosis is a common pathological feature of organ diseases resulting from excessive production of extracellular matrix, which accounts for significant morbidity and mortality. However, there is currently no effective treatment targeting fibrogenesis. Recently, metabolic alterations are increasingly considered as essential factors underlying fibrogenesis, and especially research on metabolic regulation of amino acids is flourishing. Among them, branched-chain amino acids (BCAAs) are the most abundant essential amino acids, including leucine, isoleucine and valine, which play significant roles in the substance and energy metabolism and their regulation. Dysregulation of BCAAs metabolism has been proven to contribute to numerous diseases. In this review, we summarize the metabolic regulation of fibrosis and the changes in BCAAs metabolism secondary to fibrosis. We also review the effects and mechanisms of the BCAAs intervention, and its therapeutic targeting in hepatic, renal and cardiac fibrosis, with a focus on the fibrosis in liver and associated hepatocellular carcinoma.

Acrylamide is a neurotoxin and carcinogen that forms during the thermal processing of food, inflicting irreversible harm to human health. Herein, a ratiometric fluorescence biosensor based on a 6-carboxyfluorescein-labeled aptamer (FAM-ssDNA) and porphyrin metal-organic framework (PCN-224) was developed. PCN-224 exhibits strong adsorption capacity for FAM-ssDNA and also quenches the fluorescence of FAM-ssDNA via fluorescence resonance energy transfer and photoinduced electron transfer. FAM-ssDNA hybridizes with complementary DNA to form double-stranded DNA (FAM-dsDNA), which is liberated from the PCN-224 surface, resulting in fluorescence recovery. However, the intrinsic fluorescence of the ligand remains unchanged. Acrylamide can create an adduct with FAM-ssDNA and inhibit the hybridization of FAM-dsDNA, thus realizing ratiometric sensing of acrylamide. The proposed biosensor displays excellent detection performance from 10 nM∼0.5 mM with a limit of detection of 1.9 nM. In conclusion, a fabricated biosensor was successfully applied to detect acrylamide in thermally processed food, and the results were consistent with those of high-performance liquid chromatography.

A novel ratiometric fluorescence sensor based on lanthanide-functionalized metal-organic frameworks (Ag

In this study, a fluorescence sensing platform for visual detection of hydrogen sulfide (H

Persistent usage of pesticides in agriculture has posed serious damage to overall ecosystem and human health, and thereby it is imperative to develop sensitive and efficient tools to evaluate residual pesticides in food and environmental setting. Herein, we reported a switchable colorimetric probe toward fipronil residue sensitized with aptamer-fueled catalytic activity of affiliative ZIF-8. Innovatively, it was found that the attached aptamer preferred to adsorb 3,3',5,5'-tetramethylbenzidine (TMB) rather than 2,2-azinobis (3-ethylbenzothiazo-line-6-sulfonic acid) (ABTS), greatly promoting catalytic oxidation of ZIF-8 toward TMB for further improving sensitivity. Aiding with smartphone-based image acquisition, fipronil-responsive discoloration degree was converted into the ratio of green and blue (G/B) with limit of detection as low as 0.036 μM (0.016 μg·g

A simple fluorescence and electrochemical dual-channel biosensor based on bifunctional Zr(IV)-based metal-organic framework (Zr-MOF) was proposed to detect Ochratoxin A (OTA). The bifunctional Zr-MOF, with photoluminescence properties and enormous electroactive ligands, was exploited to load OTA-specific aptamers for designing signal probes, greatly simplifying the probe-fabrication process and improving sensing reliability. Upon specific recognition of aptamer toward OTA, the anchored probe was released from the sensing interface into the reaction solution. In this circumstance, the increased amount of the signal probe in reaction solution led to an enhanced fluorescence response, while the decreased amount of the signal probe on the sensing interface resulted in a diminished electrochemical response. According to the dual-channel signal change with increasing OTA concentration, the visual fluorescence strategy was established for intuitive OTA detection, and meanwhile, sensitive electrochemical assay with a detection limit of 0.024 pg/mL was also achieved with the help of one-step electrodeposition as a sensing platform. Moreover, the proposed dual-channel assay has been successfully applied to determine OTA levels in corn samples with rapid response, superior accuracy, and high anti-interference capability, providing a promising method for food safety monitoring.

The colorimetric sensor array real-time monitoring system with multivariate analysis was established for discrimination of potato varieties with different types and degrees of corruption. The characteristic volatile compounds of fresh, dry rot and soft rot potatoes was identified by Gas Chromatography-Mass Spectrometry and the 3 × 4 array was fabricated to capture the characteristics volatile compounds. The sensor array system produced a visible color difference map upon its exposure to volatile compounds of potato. Discrimination of potatoes with the same types or different degrees of corruption was subsequently achieved using principal component analysis and hierarchical clustering analysis dendrogram. The k-nearest neighbor algorithm for potato classification provided the best results with 100 % discrimination on both the calibration and prediction sets. The linear discriminant analysis model achieved a 99.76 % calibration set and a 99.31 % prediction set for potato grading. An online warning device based on array was devised to realize unmanned monitoring for potato quality.

To better understand the diffusion behavior of NaCl during beef marinating, energy dispersive spectroscopy combined with scanning electron microscopy were used to acquire NaCl content at successive sampling points in marinated muscle, adipose and connective tissue. The NaCl content at the sampling points was substituted into a mathematical model to calculate accurate diffusion coefficients. Subsequently, geometric models containing all tissues of beef and matching the distribution characteristics of real beef were constructed and brought into COMSOL Multiphysics for simulation. The simulation results were post-processed to visualize the marinade content and its distribution state in beef. The visualization map indicated that the diffusion behavior of NaCl in different beef tissues was transient and irregular. The analysis and validation of the model demonstrated that the proposed method is generally applicable to investigate the diffusion behavior of the marinade in other meats and enables accurate control of the quality of marinated meat products.

The quality of marinated meat could be assessed by the uniformity of marinade distribution within it. In this study, the diffusion behavior of sucrose inside the marinated beef was quantitatively characterized from 2D plane and 3D space using hyperspectral imaging (HSI) and finite element analysis (FEA), respectively. Visualization of sucrose content based on HSI showed that the distribution state of sucrose on marinated beef was not uniform. Subsequently, the diffusion behavior of sucrose in the 3D beef geometric model was simulated using FEA. Results revealed that the diffusion rate of sucrose on muscle tissues is significantly higher than other tissues, and the difference in diffusion behavior is the main reason for the inhomogeneous distribution of sucrose. The quantitative characterization of marinade diffusion behavior makes it possible to predict the marinade's transient distribution state, thereby determining the optimal marinade conditions for the meat. Therefore, the method proposed has practical significance for evaluating and regulating the quality of marinated meat products.

A convenient and intuitive method for detecting trace heavy metal ions is vital for food safety and quality monitoring. Herein, a dual-emission ratiometric fluorescence probe based on Zr-based metal-organic frameworks (Zr-MOF) and silver nanoclusters (AgNCs) was assembled to sensitive and visual detect mercury ions (Hg

A dual-signal fluorescent sensor was developed for tetracycline (TET) detection in milk with excellent reproducibility and stability. In this protocol, molybdenum disulfide quantum dots (MoS

Pyrite, as a characteristic mineral in organic-rich marine shale, is a significant index for the interpretation of paleoredox conditions. In this study, based on drilling cores and focused ion beam-scanning electron microscopy (FIB-SEM), the occurrence, diameter and particle size distribution of pyrites from 32 samples obtained from the Wufeng–Longmaxi Formation in the southeast Sichuan Basin were analyzed. The results show that pyrite displays various occurrences at the macro-scale and micro-scale. At the macro-scale (mm–cm), pyrite laminations, nodular pyrites and lenticular pyrites can be found from drilling cores. At the micro-scale (nm–µm), the common occurrences of pyrite are pyrite framboids, euhedral pyrites and infilled pyrite framboids. According to the formation mechanism of pyrites, pyrites can be divided into syngenetic pyrites and diagenetic pyrites. The infilled pyrite framboids are categorized as diagenetic pyrites. The mean pyrite framboid diameters (Mean, D) range from 2.94 µm to 5.33 µm (average of 4.26 µm), with most samples showing pyrite framboid diameters from 3.5 μm to 4.8 μm. Most of the diameters of the framboid microcrystals (Mean, d) are less than 0.4 µm. Therefore, according to the (Mean, D) and the (Mean, d), the pyrite framboids can be divided into three sizes: syngenetic framboids (SF, D < 4.8 µm, d ≤ 0.4 µm), early diagenetic framboids (EDF, D > 4.8 µm, d > 0.4 µm) and late diagenetic framboids (LDF, D < 4.8 µm, d > 0.4 µm). Additionally, box-and-whisker charts of the diameter, standard deviation/skewness value of the mean diameter of pyrite framboids (Mean, D) and the ratio of trace elements indicate that the sedimentary water body was a euxinic–dysoxic environment. Euxinic conditions dominated the Wufeng Formation to the lower part of the Long11-3 section, which is beneficial for the preservation of organic matter. However, the middle-upper part of the Long13-Long12 sub-member is a dysoxic sedimentary environment.

The highly efficient detection of Salmonella typhimurium (S. typhimurium), a common foodborne bacterial, is important for the safety assurance of leafy vegetables. In this study, a fluorescent sensor (FMNCs-Apt), based on Fe3O4 magnetic nanoparticles and aptamer-modified carbon quantum dots, was developed for the rapid and highly sensitive detection of S. typhimurium in lettuce. First, carbon quantum dots were covalently bonded to the surface of prepared Fe3O4@chitosan to form magnetic fluorescence composite nanoparticles (FMNCs). Then, the aptamers of S. typhimurium were covalently linked to the surface (and named FMNCs-Apt). Fluorescence intensity of the FMNCs-Apt probes decreased as they aggregated on the surface of the bacteria, and the aggregation was separated using a magnet. Under the optimal conditions, the fluorescence change values of the solution showed a good linear relationship with the concentration of Salmonella (103-106 CFU mL-1). The detection limit of the method is 100 CFU mL-1 and 138 CFU mL-1 in fresh-cut vegetable washing solution and lettuce sample, respectively. Accordingly, this developed fluorescent probe became a highly sensitive and efficient sensor for the rapid detection of S. typhimurium in lettuce.

Supplemental Material for Rapid identification of Lactobacillus species using near-infrared spectral features of bacterial colonies by Jiyong Shi, Xuetao Hu, Xiaobo Zou, Zhiming Guo, Mel Holmes, Haroon Elrasheid Tahir, Xiaowei Huang and Zhihua Li: on behalf of the Italian Society of Hypertension and Federfarma in Journal of Near Infrared Spectroscopy

The common-law Riparian Doctrine, the legal basis for water allocation in the eastern United States, restricts qualified users along a shared waterway to reasonable withdrawals. Recent water shortages and droughts have highlighted the need for more specific withdrawal restrictions, and laws have been passed. What is still missing, however, is a water allocation mechanism that is consistent with the Riparian Doctrine and one that can accommodate downstream demands in quantifying the withdrawal limits and reservoir release rules. The present study proposes one such mechanism, called proportionally fair (ProFair) allocation, which fulfills this need. It is realized by a so-called bottleneck algorithm (BA), which allots water proportionally in a large stream network through a series of successive steps. It is discovered that the ProFair allocation can be simulated by a log-linear programming (LLP) model. The equivalence of the LLP model and the BA is proved. The Upper Neuse River watershed in North Ca...

Based on the total organic matter (TOC) content, brittle minerals (quartz + feldspar) content, total gas content, porosity and production data of eight vertical and twenty-three horizontal shale gas wells in the Sichuan Basin, a new reservoir evaluation method for the marine shale reservoirs of the Sichuan Basin is developed. In this study, based on the analytic hierarchy process (AHP) and deviation method, a comprehensive evaluation index (CEI) was proposed to evaluate the marine shale reservoir. According to the CEI and the production data, three type marine shale reservoirs were proposed. The CEI was applied to evaluate the Wufeng-Longmaxi marine shale of the B201 well. The results show that the Wufeng-Longmaxi marine shale is the low quality shale reservoir. The comprehensive evaluation criteria proposed in this study can also be applied to evaluate the marine shale reservoirs in other areas in the Sichuan Basin through the verification of several other shale gas wells in the Sichuan Basin.

Reservoir fluids refer to those fluids held in reservoir rocks under the conditions of high temperature and high pressure. Generally, reservoir fluids fall into three broad categories: (i) aqueous solutions with dissolved salts, (ii) liquid hydrocarbons, and (iii) gases (hydrocarbon and nonhydrocarbon). In all cases their compositions depend upon their source, history, and present thermodynamic conditions. Their distribution within a given reservoir depends upon the thermodynamic conditions of the reservoir as well as the petrophysical properties of the rocks and the physical and chemical properties of the fluids themselves.

In general, it is rare that there is only one phase fluid in hydrocarbon reservoir. Petroleum reservoirs contain at least two fluid phases in the porous rock: either oil and water or gas and water. In most cases, two-phase or multiphase immiscible fluids, such as oil and water, or gas and water, or oil, gas and water, coexist in reservoir.

A rock capable of producing oil, gas, or water is called reservoir rock. A reservoir rock may be any rock with sufficient porosity and permeability to allow oil and gas to accumulate and be produced in commercial quantities [1]. Petroleum generally occurs in sandstones, limestones, dolomites, conglomerates, and shales, but sometimes it is also found in igneous and metamorphic rocks.

Denitrification is known as an important pathway for nitrate loss in agroecosystems. It is important to estimate denitrification fluxes to close field and watershed N mass balances, determine greenhouse gas emissions (N2O), and help constrain estimates of other major N fluxes (e.g., nitrate leaching, mineralization, nitrification). We compared predicted denitrification estimates for a typical corn and soybean agroecosystem on a tile drained Mollisol from five models (DAYCENT, SWAT, EPIC, DRAINMOD-N II and two versions of DNDC, 82a and 82h), after first calibrating each model to crop yields, water flux, and nitrate leaching. Known annual crop yields and daily flux values (water, nitrate-N) for 1993–2006 were provided, along with daily environmental variables (air temperature, precipitation) and soil characteristics. Measured denitrification fluxes were not available. Model output for 1997–2006 was then compared for a range of annual, monthly and daily fluxes. Each model was able to estimate corn and soybean yields accurately, and most did well in estimating riverine water and nitrate-N fluxes (1997–2006 mean measured nitrate-N loss 28 kg N ha−1 year−1, model range 21–28 kg N ha−1 year−1). Monthly patterns in observed riverine nitrate-N flux were generally reflected in model output (r 2 values ranged from 0.51 to 0.76). Nitrogen fluxes that did not have corresponding measurements were quite variable across the models, including 10-year average denitrification estimates, ranging from 3.8 to 21 kg N ha−1 year−1 and substantial variability in simulated soybean N2 fixation, N harvest, and the change in soil organic N pools. DNDC82a and DAYCENT gave comparatively low estimates of total denitrification flux (3.8 and 5.6 kg N ha−1 year−1, respectively) with similar patterns controlled primarily by moisture. DNDC82h predicted similar fluxes until 2003, when estimates were abruptly much greater. SWAT and DRAINMOD predicted larger denitrification fluxes (about 17–18 kg N ha−1 year−1) with monthly values that were similar. EPIC denitrification was intermediate between all models (11 kg N ha−1 year−1). Predicted daily fluxes during a high precipitation year (2002) varied considerably among models regardless of whether the models had comparable annual fluxes for the years. Some models predicted large denitrification fluxes for a few days, whereas others predicted large fluxes persisting for several weeks to months. Modeled denitrification fluxes were controlled mainly by soil moisture status and nitrate available to be denitrified, and the way denitrification in each model responded to moisture status greatly determined the flux. Because denitrification is dependent on the amount of nitrate available at any given time, modeled differences in other components of the N cycle (e.g., N2 fixation, N harvest, change in soil N storage) no doubt led to differences in predicted denitrification. Model comparisons suggest our ability to accurately predict denitrification fluxes (without known values) from the dominant agroecosystem in the midwestern Illinois is quite uncertain at this time.

Some of the largest riverine N fluxes in the continental USA have been observed in agricultural regions with extensive artificial subsurface drainage, commonly called tile drainage. The degree to which high riverine N fluxes in these settings are due to high net N inputs (NNI), greater transport efficiency caused by the drainage systems, or other factors is not known. The objective of this study was to evaluate the role of tile drainage by comparing NNI and riverine N fluxes in regions of Illinois with similar climate and crop production practices but with different intensities of tile drainage. Annual values of NNI between 1940 and 1999 were estimated from county level agricultural production statistics and census estimates of human population. During 1945–1961, riverine nitrate flux in the extensively tile drained region averaged 6.6 kg N ha−1 year−1 compared to 1.3 to 3.1 kg N ha−1 for the non-tile drained region, even though NNI was greater in the non-tile drained region. During 1977–1997, NNI to the tile-drained region had increased to 27 kg N ha−1 year−1 and riverine N flux was approximately 100% of this value. In the non-tile-drained region, NNI was approximately 23 kg N ha−1 year−1 and riverine N flux was between 25% and 37% of this value (5 to 9 kg N ha−1 year−1). Denitrification is not included in NNI and, therefore, any denitrification losses from tile-drained watersheds must be balanced by other N sources, such as depletion of soil organic N or underestimation of biological N fixation. If denitrification and depletion of soil organic N are significant in these basins, marginal reductions in NNI may have little influence on riverine N flux. If tile drained cropland in Illinois is representative of the estimated 11 million ha of tile drained cropland throughout the Mississippi River Basin, this 16% of the drainage area contributed approximately 30% of the increased nitrate N flux in the Lower Mississippi River that occurred between 1955 and the 1990s.