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In our study, we have tested the effects of sonication and hydrothermal treatments on the properties of carbon dots synthesized from a microwave-assisted method (C-dotsMW). When the carbon dots are sonicated in an aerobic environment, the fluorescence quantum yield decreases drastically because the molecular fluorophores attached to the surface of the carbon dots are oxidized during the sonication process. Meanwhile, the sonicated C-dotsMW also lose their Hg2+ ion sensing and photoreduction activity due to the oxidization of surface functional groups. After the hydrothermal treatment, the fluorescence quantum yield of C-dotsMW increases due to the formation of new fluorophores; however, the Hg2+ ion sensitivity and photoreduction activity of C-dotsMW decrease significantly due to the oxidization of surface functional groups. By autoclaving the C-dotsMW at 100 °C, we have demonstrated that we can enhance the fluorescence quantum yield of C-dotsMW without losing their Hg2+ ion sensitivity. This finding can be used to improve the fluorescence quantum yield of the fluorescent ion sensor based on C-dots.

Sour gas reservoirs are an important part of unconventional gas reservoirs, which are widely distributed in the world. However, elemental sulfur deposition, channel plugging, and productivity reduction consequentially occur in the development of high sour gas fields as pressure drops. The accurate prediction of sulfur deposition is a very important work for sour gas reservoirs. In this paper, a fractal model is presented for predicting elemental sulfur saturation in the presence of natural fracture. The model takes into consideration the effects of non-Darcy flow. In addition, the influence parameters such as fractal dimension, fractal index, and non-Darcy flow are studied. The results showed the following: (1) sulfur deposition was overestimated by Hu’s model, and this paper model is more accurate for prediction of sulfur deposition; (2) elemental sulfur deposition decreases with the increase of the fractal dimension, while elemental sulfur deposition increases with the decrease of the fractal index; and (3) non-Darcy flow should be considered because it causes a faster rate of sulfur deposition. This research will provide a basis and reference for predicting elemental sulfur saturation in the presence of natural fracture for sour gas reservoirs.

A suite of carbon materials is prepared from biochar and coal at three different blending ratios with 10, 20, and 30% biochar by mass. These carbon materials are activated by steam to obtain porous structures. The effect of the inactivated and activated carbon materials on the cracking of coal pyrolysis volatiles is evaluated. The results indicate that the inactivated carbon materials are beneficial to improve the yield of light oil with a boiling point below 170 °C. The steam-activated carbon materials are more conducive to cracking tar pitch than the inactivated carbon materials due to the increased defects in carbon structure. However, it is also easy to form more coke deposits. More components rich in hydrogen are cracked to generate radicals that could combine with the phenols' precursor over carbon materials, and the content of phenols in tar is increased. The carbon materials prepared from biochar and coal using this method show distinct advantages as filter media in the granular bed duster. It can improve the quality of tar along with reducing the dust content in tar.

As one of the most widely used materials, plastic polymer fragments can abrasively degrade into microplastic (MP) and smaller nanoplastic (NP) particles. The present study aimed to investigate the influence of particle size on neurodevelopmental toxicity induced by polystyrene nanoplastics (PS-NPs) in Caenorhabditis elegans and to explore the underlying potential mechanism. C. elegans were exposed to different concentrations of PS-NPs with various sizes (25, 50, and 100 nm) for 72 h. Our results showed that all of these PS-NPs could dose-dependently induce an increase in reactive oxygen species production and mitochondrial damage in C. elegans, resulting in inhibition of body length, head thrashes, body bending, and dopamine (DA) contents. A weaker neurotoxicity was found in 25 nm PS-NPs compared to 50 and 100 nm PS-NPs, which might be due to preferential cellular distribution and greater polymerization capability of the smaller particles. In addition, all these PS-NPs could induce lipofuscin accumulation and apoptosis independent of particle size, suggesting that oxidative damage and mitochondrial dysfunction may not be the only way responsible for NP-induced neurotoxic effects. Furthermore, the mutant test targeting two presenilin genes (sel-12 and hop-1) showed that sel-12 and hop-1 were involved in regulation of PS-NP-induced neurodevelopmental toxicity and mitochondrial damage. In conclusion, PS-NPs could induce neurodevelopmental toxicity dependent on particle sizes mediated by mitochondrial damage and DA reduction. Enhanced expression of presenilin plays a role in PS-NP-induced oxidative stress and neurodevelopmental toxicity.

Fracturing measures are common practice for horizontal wells of tight oil reservoirs. Thus, production estimation is a significant problem that should be solved. However, previous models for the production of fractured horizontal wells of tight oil reservoirs have some problems. In this paper, we present a semi-analytical model based on the volumetric source method to simulate production from nonplanar fracture geometry in a tight oil reservoir. First, we developed an analytical model based on the volumetric source method in nonplanar fracture geometry with varying widths. Second, the model was coupled with fracture flow and solved by the Gauss–Seidel iteration. Third, the semi-analytical model was verified by a numerical reservoir simulator. Finally, sensitivity analysis was conducted for several critical parameters. Results of validations showed good agreement between this paper’s model and the numerical reservoir simulator. The results from the sensitivity analysis showed that (1) production increases with an increased number of fracture segments; (2) production drops more quickly with a smaller fracture half-length in the first stage, and it drops slowly with a smaller fracture half-length in the second stage; (3) cumulative production increases more quickly with a bigger fracture conductivity; and (4) cumulative oil production from a fracture with a constant width and without stress sensitivity coefficient is smaller than that from a fracture with varying widths and with stress sensitivity coefficient. This research provides a basis and reference for production estimation in tight oil reservoirs.

A perfluorosulfonic acid (PFSA) ionomer, used as the proton conductor in the catalyst layer, influences significantly the performance of proton exchange membrane fuel cell catalyst-coated membrane (CCM). In this paper, SSC-CCM is prepared by the SSC-PFSA (Aquivion, EW 720) ionomer, and the comparative sample (LSC-CCM) is based on the LSC-PFSA ionomer (Nafion, EW 1100). Compared with LSC-CCM, SSC-CCM shows higher porosity, larger electrochemical surface area (ECSA), and smaller high-frequency resistance. Polarization curves of SSC-CCM tested by the short stack show better performance than those of LSC-CCM, especially under the lower relative humidity operations. Moreover, the SSC-CCM outputs higher voltage and is more stable in the dynamic process with temperature continuously increasing under lower relative humidity operation. Such excellent performance of SSC-CCM is confirmed from the higher proton conductivity of SSC-PFSA under low relative humidity. These results indicate that the SSC-PFSA ionomer could be employed for the CCM catalyst layer under the operation conditions of low relative humidity and dynamic running for automotive applications.

The KDM4/JMJD2 Jumonji C-containing histone lysine demethylases (KDM4A−KDM4D), which selectively remove the methyl group(s) from tri/dimethylated lysine 9/36 of H3, modulate transcriptional activation and genome stability. The overexpression of KDM4A/KDM4B in prostate cancer and their association with androgen receptor suggest that KDM4A/KDM4B are potential progression factors for prostate cancer. Here, we report the crystal structure of the KDM4B·pyridine 2,4-dicarboxylic acid· H3K9me3 ternary complex, revealing the core active-site region and a selective K9/K36 site. A selective KDM4A/ KDM4B inhibitor, 4, that occupies three subsites in the binding pocket is identified by virtual screening. Pharmaco- logical and genetic inhibition of KDM4A/KDM4B significantly blocks the viability of cultured prostate cancer cells, which is accompanied by increased H3K9me3 staining and transcriptional silencing of growth-related genes. Significantly, a substantial portion of differentially expressed genes are AR-responsive, consistent with the roles of KDM4s as critical AR activators. Our results point to KDM4 as a useful therapeutic target and identify a new inhibitor scaffold.