Enhancement of the Wettability and Lubrication of Shale Rock via Nanoemulsions

Nanoemulsions have been widely used as additives for drilling fluids in recent years. With the development of nanotechnology, multifunctional nanomaterials have been added to nanoemulsions. The improvement of wettability of the surfaces, alteration of oil-wet on shale rock surfaces, and environmentally friendly conditions are considered as the future development directions of nanoemulsions. In this work, a novel nanoemulsion was prepared by using hydrocarbon-based polyoxyethylene ether, oil (hydrocarbon), distilled water, and formation crude oil as the main raw materials. The shale rocks before and after immersion with as-prepared nanoemulsion were characterized by contact angle measurement, atomic force microscope (AFM), and Fourier transform infrared spectroscopy (FTIR). It is clearly observed that the nanoemulsion greatly improved the wettability of the sandstone and rock surface by forming a layer of active agent film on the surface of the rock. The as-prepared nanoemulsion had good ability to curb the anticollapse and lubricate and protect the oil and gas layer

Microcystin aids in cold temperature acclimation: Differences between a toxic Microcystis wildtype and non-toxic mutant

For Microcystis aeruginosa PCC 7806, temperature decreases from 26 °C to 19 °C double the microcystin quota per cell during growth in continuous culture. Here we tested whether this increase in microcystin provided M. aeruginosa PCC 7806 with a fitness advantage during colder-temperature growth by comparing cell concentration, cellular physiology, reactive oxygen species damage, and the transcriptomics-inferred metabolism to a non-toxigenic mutant strain M. aeruginosa PCC 7806 ΔmcyB. Photo-physiological data combined with transcriptomic data revealed metabolic changes in the mutant strain during growth at 19 °C, which included increased electron sinks and non-photochemical quenching. Increased gene expression was observed for a glutathione-dependent peroxiredoxin during cold treatment, suggesting compensatory mechanisms to defend against reactive oxygen species are employed in the absence of microcystin in the mutant. Our observations highlight the potential selective advantages of a longer-term defensive strategy in management of oxidative stress (i.e., making microcystin) vs the shorter-term proactive strategy of producing cellular components to actively dissipate or degrade oxidative stress agents

The Occurrence of Microcystin-LR Photoisomerization Products in a New York State Local Lake

The hepatotoxin, Microcystin-LR (MC-LR) is common in New York State lakes. Microcystins undergoes a photochemical isomerization to form several photoisomerization products. These photoisomerization products were generated in the laboratory, characterized by high-field NMR spectroscopy, and an in-house LC-MS microcystin method modified to allow for their detection in natural waters. Lake Neatahwanta (Fulton County, NY) experiences persistent cyanobacteria blooms. Samples were taken weekly from the Lake Neatahwanta during the 2016 and 2017 bloom season to measure the occurrence and concentration of these photoisomerization products in the lake. The products were detected in ~95% of samples and had a strong positive correlation with the in-situ concentration of MC-LR. The proportion of photoisomerization products were higher in dissolved phase than in the particulate phase. There was no significant daily variation observed in a diurnal experiment conducted in both 2016 and 2017. Different analytical method (LC-MS, LC-MSMS and ELISA) were evaluated for their ability to detect these photoisomerization products. This study provides important information on the fate of microcystins in natural waters and the impact of these products on different microcystin detection methods

An Improved Prediction Model Combining Inverse Exponential Smoothing and Markov Chain

On the basis of the triple exponential smoothing prediction model, this paper introduces the reverse prediction idea and establishes the reverse triple exponential smoothing model by setting parameters such as threshold value and iteration times and reasonably correcting its initial value. This method can effectively reduce the error of early prediction value. At the same time, aiming at the problem that the predicting advantage of the reverse triple exponential smoothing model weakens in the later period, Markov theory is introduced to correct its error value, and an improved prediction model combining inverse exponential smoothing and Markov chain is further established. The improved model combines the advantages of index model trend prediction and Markov fluctuation prediction, and the prediction accuracy and stability of the model are significantly improved through case tests

Panax ginseng improves physical recovery and energy utilization on chronic fatigue in rats through the PI3K/AKT/mTOR signalling pathway

AbstractContext Panax ginseng C. A. Meyer (Araliaceae) is a tonic herb used in ancient Asia.Objective This study investigated the antifatigue effect of P. ginseng on chronic fatigue rats.Materials and methods Sprague-Dawley rats were divided into control, model and EEP (ethanol extraction of P. ginseng roots) (50, 100 and 200 mg/kg) groups (n = 8). The rats were subcutaneously handled with loaded swimming once daily for 26 days, except for the control group. The animals were intragastrically treated with EEP from the 15th day. On day 30, serum, liver and muscles were collected, and the PI3K/Akt/mTOR signalling pathway was evaluated.Results The swimming times to exhaust of the rats with EEP were significantly longer than that without it. EEP spared the amount of muscle glycogen, hepatic glycogen and blood sugar under the chronic state. In addition, EEP significantly (p < 0.05) decreased serum triglycerides (1.24 ± 0.17, 1.29 ± 0.04 and 1.20 ± 0.21 vs. 1.58 ± 0.13 mmol/L) and total cholesterol (1.64 ± 0.36, 1.70 ± 0.15 and 1.41 ± 0.19 vs. 2.22 ± 0.19 mmol/L) compared to the model group. Regarding the regulation of energy, EEP had a positive impact on promoting ATPase activities and relative protein expression of the PI3K/Akt/mTOR pathway.Conclusions Our results suggested that EEP effectively relieved chronic fatigue, providing evidence that P. ginseng could be a potential dietary supplement to accelerate recovery from fatigue

Research on the Shearer Positioning Method Based on the MEMS Inertial Sensors/Odometer Integrated Navigation System and RTS Smoother

The shearer positioning method with an inertial measurement unit and the odometer is feasible in the longwall coal-mining process. However, the positioning accuracy will continue to decrease, especially for the micro-electromechanical inertial measurement unit (MIMU). In order to further improve the positioning accuracy of the shearer without adding other external sensors, the positioning method of the Rauch-Tung-Striebel (RTS) smoother-aided MIMU and odometer is proposed. A Kalman filter (KF) with the velocity and position measurements, which are provided by the odometer and closing path optimal estimation model (CPOEM), respectively, is established. The observability analysis is discussed to study the possible conditions under which the error states of KF can be estimated. A RTS smoother with the above-mentioned KF as the forward filter is built. Finally, the experiments of simulating the movement of the shearer through a mobile carrier were carried out, with a longitudinal movement distance of 44.6 m and a lateral advance distance of 1.2 m. The results show that the proposed method can effectively improve the positioning accuracy. In addition, the odometer scale factor and mounting angles can be estimated in real time

Spatial and Temporal Variation in Paralytic Shellfish Toxin Production by Benthic Microseira (Lyngbya) wollei in a Freshwater New York Lake

Butterfield Lake is a mesotrophic lake in New York State where residents and pets have experienced unexplained health issues. Microseira wollei (basionym Lyngbya wollei) was found at two of 15 sites in Butterfield Lake and analyzed for microcystins, anatoxins, cylindrospermopsins, and paralytic shellfish poisoning toxins (PSTs). Only PSTs and trace levels of anatoxin-a were detected in these samples. This is the first published report of PSTs within a New York State lake. To evaluate the environmental and temporal drivers leading to the observed toxicity, PST content at the two sites was examined in detail. There were distinct differences in the total PST content, filament nutrient, filament chlorophyll, and relationship to environmental drivers between the sites, as well as distinct differences in the total PST content measured using different analytical techniques. A multivariate model containing site, temperature, and filament chlorophyll explained 85% of the variation in PSTs observed over the growing season. This work emphasizes the importance of proper site selection and choice of analytical technique in the development of monitoring programs to protect lake users from the occurrence of benthic cyanobacteria toxins

Microcystin aids in photo-acclimation during prolonged cold stress treatment in Microcystis aeruginosa strain PCC7806

Microcystis aeruginosa PCC7806 has been shown to increase toxin production in response to prolonged cold stress. To test whether this increase in toxin production is a beneficial adaptation that aids in cold fitness, the non-toxic mutant Microcystis aeruginosa PCC 7806 ΔmcyB was grown in duplicate chemostat cultures alongside chemostats containing the wildtype isolate. Strains reached steady-state at 26℃, then were subjected to an 11-day shift to 19℃, followed by a reversion back to 26℃. Throughout the experimental period, samples were collected to measure cell abundance, excitation pressure, effective quantum yield, microcystin production, reactive oxygen species (ROS) formation, and for RNA-seq analyses. During the 19℃ period, the mutant experienced elevated excitation pressure and ROS formation relative to the wildtype strain. Microcystin quota doubled in the wildtype strain by day 7 of the 19℃ treatment, followed by decreased effective quantum yields 24 h later. This was not observed in the mutant strains. Both mutant and wildtype populations began to recover after 8 days at 19℃. Microcystin did not aid in growth recovery during cold stress, although it seemed to play a part in the photo-acclimatory process based on excitation pressure and quantum yield readings

Toxin Dynamics among Populations of the Bioluminescent HAB Species <i>Pyrodinium bahamense</i> from the Indian River Lagoon, FL

Dinoflagellate species that form some of the most frequent toxic blooms are also bioluminescent, yet the two traits are rarely linked when studying bloom development and persistence. P. bahamense is a toxic, bioluminescent dinoflagellate that previously bloomed in Florida with no known record of saxitoxin (STX) production. Over the past 20 years, STX was identified in P. bahamense populations. The goal of this study was to examine toxin dynamics and associated molecular mechanisms in spatially and temporally distinct P. bahamense populations from the Indian River Lagoon, FL. SxtA4 is a key gene required for toxin biosynthesis. SxtA4 genotype analysis was performed on individual cells from multiple sites. Cell abundance, toxin quota cell−1, and sxtA4 and RubisCo (rbcL) transcript abundance were also measured. There was a significant negative correlation between cell abundance and toxin quota cell−1. While the sxtA4+ genotype was dominant at all sites, its frequency varied, but it occurred at 90–100% in many samples. The underlying mechanism for toxin decrease with increased cell abundance remains unknown. However, a strong, statistically significant negative correlation was found between stxA4 transcripts and the sxtA4/rbcL ratio, suggesting cells make fewer sxtA4 transcripts as a bloom progresses. However, the influence of sxtA4− cells must also be considered. Future plans include bioluminescence measurements, normalized to a per cell basis, at sites when toxicity is measured along with concomitant quantification of sxtA4 gene and transcript copy numbers as a means to elucidate whether changes in bloom toxicity are driven more at the genetic (emergence of sxtA4− cells) or transcriptional (repression of sxtA4 in sxtA4+ cells) level. Based on the results of this study, a model is proposed that links the combined traits of toxicity and bioluminescence in P. bahamense bloom development