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Based on the study of the distribution of intra-platform shoals and the characteristics of dolomite reservoirs in the Middle Permian Qixia Formation in the Gaoshiti–Moxi area of the Sichuan Basin, SW China, the controlling factors of reservoir development were analyzed, and the formation model of “intra-platform shoal thin-layer dolomite reservoir” was established. The Qixia Formation is a regressive cycle from bottom to top, in which the first member (Qi1 Member) develops low-energy open sea microfacies, and the second member (Qi2 Member) evolves into intra-platform shoal and inter-shoal sea with decreases in sea level. The intra-platform shoal is mainly distributed near the top of two secondary shallowing cycles of the Qi2 Member. The most important reservoir rock of the Qixia Formation is thin-layer fractured-vuggy dolomite, followed by vuggy dolomite. The semi-filled saddle dolomite is common in fracture-vug, and intercrystalline pores and residual dissolution pores combined with fractures to form the effective pore-fracture network. Based on the coupling analysis of sedimentary and diagenesis characteristics, the reservoir formation model of “pre-depositional micro-palaeogeomorphology controlling shoal, sedimentary shoal controlling dolomite, penecontemporaneous dolomite benefiting preservation of pores, and late hydrothermal action effectively improving reservoir quality” was systematically established. The “first-order high zone” micro-paleogeomorphology before the deposition of the Qixia Formation controlled the development of large area of intra-platform shoals in Gaoshiti area during the deposition of the Qi2 Member. Shoal facies is the basic condition of early dolomitization, and the distribution range of intra-platform shoal and dolomite reservoir is highly consistent. The grain limestone of shoal facies is transformed by two stages of dolomitization. The penecontemporaneous dolomitization is conducive to the preservation of primary pores and secondary dissolved pores. The burial hydrothermal fluid enters the early dolomite body along the fractures associated with the Emeishan basalt event, makes it recrystallized into medium–coarse crystal dolomite. With the intercrystalline pores and the residual vugs after the hydrothermal dissolution along the fractures, the high-quality intra-platform shoal-type thin-layer dolomite reservoirs are formed. The establishment of this reservoir formation model can provide important theoretical support for the sustainable development of Permian gas reservoirs in the Sichuan Basin.

Abundant light and heat in the Hexi Oasis Irrigation Area in China provide superior natural conditions for agricultural development. To study the maize–soybean planting system of intercropping and determine superior group yield and economic benefits in the Hexi Oasis Irrigation Area, eight treatments were set up in 2022–2023: maize–soybean intercropping with a bandwidth of 1.8 m and a row ratio of 2:3 (M1S3), a bandwidth of 1.8 m and a row ratio of 2:4 (M1S4), a bandwidth of 2.0 m and a row ratio of 2:3 (M2S3), a bandwidth of 2.0 m and a row ratio of 2:4 (M2S4), a bandwidth of 2.2 m and a row ratio of 2:3 (M3S3), a bandwidth of 2.2 m and a row ratio of 2:4 (M3S4), monocropping maize (M), and monocropping soybean (S). We analyzed the effects of changes in bandwidth–row ratios on photosynthetic characteristics, yield, and interspecific relationships in these treatments during two crop reproductive periods. Our results showed the following: (1) Under the intercropping system, the photosynthetic capacity of maize was highest when the row ratio was 2∶3 and bandwidth was 1.8 m. The net photosynthetic rate (Pn) increased by 1.72% to 48.90%, the transpiration rate (Tr) increased by 5.53% to 118.10%, and stomatal conductance (Gs) increased by 2.82% to 86.49% compared with other planting systems. Increasing the bandwidth from 1.8 m to 2.2 m improved the photosynthetic characteristics of soybean, increasing Pn, Tr, and Gs by 3.44% to 74.21%, 3.92% to 53.69%, and 2.41% to 55.22%, respectively. (2) The yield of maize and soybean under monocropping was significantly higher than that under intercropping. In the intercropping treatments, the average yield of crops in the M3S3 system was 16,519.4 kg ha−1, an increase of 6.48% compared with the M3S4 system, indicating that the reduction of one row of soybean in the same bandwidth system increases crop yield; The average economic benefit of the M3S3 system over two years was 35,171.73 CNY ha−1, which increased by 13.3 and 80% compared with the average economic benefit of maize and soybean monocropping, indicating that the intercropping system leads to better economic results for farmers than monocropping. (3) In the two-year experiment, the land equivalent ratio (LER) was highest in the M3S3 model, averaging 1.25 over the two years, showing better land productivity compared with other intercropping systems. (4) When bandwidth was 1.8, 2.0, or 2.2 m, the LER decreased by 8.3, 5.9, and 5.6% when planting an additional row of soybeans, the relative crowding coefficient of soybeans in the respective bandwidths increased by 4.59, 4.72, and 0.75%, the competition ratio of maize (CRM) increased by 22.94, 16.97, and 12.74%, the competition ratio of soybean (CRS) decreased by 20.47, 17.61, and 16.78%, and the competitive power of maize was greater than that of soybean, indicating that the increase in soybean rows in the same bandwidth system would weaken the competitive advantage of soybean, resulting in crop yield and economic benefit reduction. When the row ratio was 2:3 or 2:4, bandwidth increased from 1.8 m to 2.2 m, LER decreased by 3.31 and 0.86%, intercropping maize aggressiveness (AM) decreased by 7.55 and 12.50%, CRM decreased by 18.04 and 24.84%, and CRS increased by 17.32 and 22.77%, respectively, which indicated that the increase in bandwidth under different row ratio systems could improve the competitive advantage of intercropping soybean, thereby improving crop yield and economic benefits. (5) The AHP method, entropy weight method, and TOPSIS analysis showed that M3S3 ranked first, with the highest comprehensive evaluation (0.6017). In conclusion, the M3S3 planting system can better coordinate crop interspecies relationships, with higher land yield and economic benefit, and can be used as a suitable maize–soybean intercropping system in the Hexi oasis irrigation area.

Abstract Background Thoracic aortic aneurysm or dissections (TAADs) represent a group of life-threatening diseases. Genetic aetiology can affect the age of onset, clinical phenotype, and timing of intervention. We conducted a prospective trial to determine the prevalence of pathogenic variants in TAAD patients and to elucidate the traits related to harbouring the pathogenic variants. One hundred and one unrelated TAAD patients underwent genetic sequencing and analysis for 23 TAAD-associated genes using a targeted PCR and next-generation sequencing-based panel. Results A total of 47 variants were identified in 52 TAAD patients (51.5%), including 5 pathogenic, 1 likely pathogenic and 41 variants of uncertain significance. The pathogenic or likely pathogenic (P/LP) variants in 4 disease-causing genes were carried by 1 patient with familial and 5 patients with sporadic TAAD (5.9%). In addition to harbouring one variant causing familial TAAD, the FBN1 gene harboured half of the P/LP variants causing sporadic TAAD. Individuals with an age of onset less than 50 years or normotension had a significantly increased genetic risk. Conclusions TAAD patients with a younger age at diagnosis or normotension were more likely to carry a P/LP variant; thus, routine genetic testing will be beneficial to a better prognosis through genetically personalized care prior to acute rupture or dissection.

Instruction: Due to the declining production rate of conventional natural gas reservoir and the rising demand for natural gas resources, conventional natural gas resources cannot satisfy the needs of economic development. Unconventional gas resource is considered to be the most promising energy supplement, therefore it is an inevitable trend to explore and develop unconventional oil and gas resources such as low permeability reservoirs. At present, the carbonate gas reservoirs in the high permeability area of Sichuan Basin have been almost fully developed, while the remaining gas reservoirs in the low permeability area are not well developed. However, the key factors for effectively enhancing gas recovery rate in different types of low permeability reservoirs are not the same. Even gas reservoirs with the same macroscopic geological characteristics will show different development characteristics through the production processes.Method: In order to analyze the factors affecting the effective production rate of low-permeability gas reservoirs, it is necessary to conduct research from the microscopic perspective, to reveal the effective production conditions of natural gas in low-permeability reservoirs. In this study, low-permeability carbonate samples of Sinian Dengying Formation from Sichuan Basin were taken. Micro-CT scanning technology was used to obtain core images for the carbonate rocks, and the digital carbonate core models at microscopic scale were reconstructed. Based on the reconstructed carbonate digital core models, LBM method was applied to obtain the absolute permeability of the core models.Results: The results imply that the porosity, pore area fraction, throat area fraction, mean throat length, shape factor, coordination number and tortuosity are the factors affecting the absolute permeability of carbonate rocks.Discussion: Subsequently, the relationship between different pore structure parameters and absolute permeability was obtained by multi-parameter fitting method, which provided a new research method for directly predicting the absolute permeability of carbonate rocks by using pore structure parameters.

The second member of Triassic Feixianguan Formation in Jiulongshan area of northwestern Sichuan Basin has made breakthroughs in natural gas exploration and has great exploration potential. Drilling data show that the second section of Feixianguan Formation has developed multiple sets of reservoirs, which are mainly concentrated in the upper sub-member of the second member of Feixianguan Formation. The overall heterogeneity is strong, the lithology and physical properties are complex and changeable, the reservoir thickness is thin, and drilling is less, so it is difficult to determine the spatial distribution characteristics of oolitic beach reservoir, which restricts the natural gas exploration process in this area. For the oolitic beach reservoir in the upper sub-member of the second member of Feixianguan Formation of Jiulongshan area, using downhole reservoir characteristics and 3D seismic data, the reflection characteristics of oolitic beach reservoir are analyzed, and then the seismic response model of oolitic beach reservoir is established by forward modeling. It is clear that the seismic response characteristics of the reservoir in this area are weak amplitude-continuous reflection; through the use of layer flattening impression method to restore the ancient landscape of the second section of Feixianguan Formation, combined with seismic facies analysis and seismic amplitude attribute characteristics, The distribution characteristics of favorable facies belt for oolitic beach development are determined. Based on the distribution of favorable facies belt, this paper uses the relative impedance-based tuning amplitude inversion and waveform difference inversion method to make a fine prediction of the spatial distribution of the reservoir, defines the spatial distribution characteristics of the reservoir, and predicts the thickness and fracture development of oolitic beach reservoir. The prediction results of the reservoir thickness are in good agreement with the actual drilling results, which confirms the application of this prediction method in this area. According to the fracture development, wave impedance value less than 1.6×106 g/(cm2·s), reservoir thickness, and other indicators, the favorable development area of oolitic beach reservoir is further delineated, which provides a favorable basis for the next exploration and development.

The dolomite reservoir of the fourth member of Dengying Formation in Moxi area of Sichuan Basin is thin, is fast in lateral variation, and has P-impedance difference from the surrounding rock; it is difficult to identify and predict the dolomite reservoir and fluid properties by conventional poststack seismic inversion. Through the correlation analysis of core test data and logging P-S-wave velocity, this work proposed a formula to calculate the shear wave velocity in different porosity ranges and solved the issue that some wells in the study area have no S-wave logging data. AVO forward analysis reveals that whether the gas reservoir of dolomite reservoir is located at the top of the fourth member of Dengying Formation is the main factor affecting the variation of AVO type. Through cross-plotting analysis of elastic parameters, it is found that P-S-wave velocity ratio and fluid factor are sensitive parameters to gas-bearing property of dolomite reservoir in the study area. By comparing the inversion results of prestack parameters such as density, P-wave impedance, S-wave impedance, P-S-wave velocity ratio, and fluid factor, it is found that the gas-bearing prediction of dolomite reservoir by using P-S-wave velocity ratio and fluid factor obtained from simultaneous prestack inversion had the highest coincidence rate with actual drilling data. At last, according to the distribution characteristics of fluid factor and P-S-wave velocity ratio, the favorable gas-bearing areas of dolomite reservoir in the fourth member of Dengying Formation in the study area are finely predicted, and the next favorable exploration areas were pointed out.

Carbonate reservoirs significantly contribute to exploitation. Due to their strong heterogeneity, it is of great significance to study core seepage capacity and gas-water two-phase flow of reservoirs with various pore structures under different stresses for productivity prediction, gas reservoir development, and reservoir protection. We utilize micrometer-resolution X-ray tomography to obtain the digital rocks of porous, fractured-porous, and fractured-vuggy carbonate rocks during pressurized process and depressurization. The Lattice Boltzmann method and pore network model are used to simulate the permeability and gas-water two-phase flow under different confining pressures. We show that at the early stage of pressure increase, fractures, vugs, or large pores as the main flow channels first undergo compaction deformation, and the permeability decreases obviously. Then, many isolated small pores are extruded and deformed; thus, the permeability reduction is relatively slow. As the confining pressure increases, the equal-permeability point of fractured-porous sample moves to right. At the same confining pressure, the water saturation corresponding to equal-permeability point during depressurization is greater than that of pressurized process. It is also proved that the pore size decreases irreversibly, and the capillary force increases, which is equivalent to the enhancement of water wettability. Therefore, the irreversible closure of pores leads to the decrease of permeability and the increase of gas-phase seepage resistance, especially in carbonate rocks with fractures, vugs, and large pores. The findings of this study are helpful to better understand the gas production law of depletion development of carbonate gas reservoirs and provide support for efficient development.

Abstract Polylactic acid (PLA) is a versatile and biodegradable scaffold widely used in biomedical fields to repair tissue defects. Exosomes derived from mesenchymal stem cells (MSCs) are nano-sized extracellular vesicles, which play an important role in tissue engineering in recent years. The primary focus of this study was to develop a bioactive 3D PLA scaffold using exosome-based strategy to improve its osteogenic and immunoregulatory potential. We firstly successfully isolated MSC-derived exosomes (MSC-Exo). Morphological analysis revealed that MSC-Exo exhibits a typical cup-shaped morphology with high expression of exosomal marker CD63. MSC-Exo internalization into recipient cells were also investigated using flow cytometry and confocal laser scanning microscopy. Porous 3D PLA scaffold coated MSC-Exo were used for immunoregulatory and osteogenic testing. Exosomes released from 3D PLA scaffold were validated in RAW264.7 and hBMSCs. The cell proliferation and live/dead assay indicated high biocompatibility for PLA-Exo scaffold. Additionally, PLA-Exo scaffold could reduce the pro-inflammatory marker expression and reactive oxygen species (ROS) production, indicating potential immunoregulatory potential. It is also confirmed that PLA-Exo scaffold could potentiate osteogenic differentiation in the osteogenesis assay. In conclusion, our results demonstrate this bioactive 3D-printed PLA scaffolds with MSC-Exo modification holds immunoregulatory potential and favor osteogenic differentiation, thus having potential applications in bone tissue regeneration.

Natural gas hydrate is a kind of clean energy with huge reserves, and the saturation (volume percentage of hydrate in pore space of sediments) is the key parameter for determining whether the reservoir is worthy of exploitation. In this work, rapid hydrate dissociation by the combination of heat injection and NaCl inhibitor addition was studied, and an on-site evaluation method for hydrate saturation in sediment samples was proposed by using a core sampler to transfer hydrate samples under pressure. The results showed that the average gas production rate per unit volume was increased significantly to reach 7.22 L/Lr·min-1 by the injection of NaCl aqueous solution with 50.9 °C, which was attributed to the increase of the chemical potential to further accelerate the rate of hydrate dissociation in the presence of NaCl. Furthermore, for the measurement of methane hydrate samples saturation with a volume of 673 cm3 (which contained 1.4 mol hydrates with the saturation of 58%), hydrate saturation could be accurately achieved within 30 min with a relative error lower than 11.7% This work may provide new thoughts for on-site saturation evaluation and rapid dissociation of hydrate samples during natural gas hydrate exploitation.

As an alternative route for aromatics and hydrogen production, methane dehydroaromatization (MDA) is of significant academic and industrial interest due to the abundance of natural gas resources and the intensive demand for aromatics and COx-free hydrogen. In the present work, a simulation study on MDA in membrane reactors (MRs) was performed with the aim of co-producing aromatics and COx-free hydrogen with a highly improved efficiency. The effects of various parameters, including catalytic activity, membrane flux and selectivity, as well as the operating conditions on the MR performance were discussed with respect to methane conversion, hydrogen yield, and hydrogen purity. The results show that catalytic activity and membrane flux and selectivity have significant impacts on CH4 conversion and H2 yield, whereas H2 purity is mainly dominated by membrane selectivity. A highly improved MDA is confirmed to be feasible at a relatively low temperature and a high feed pressure because of the hydrogen extraction effect. To further improve MDA in MRs by intensifying H2 extraction, a simple configuration combining a fixed-bed reactor (FBR) and an MR together is proposed for MDA, which demonstrates good potential for the high-efficiency co-production of aromatics and COx-free hydrogen.

It is a safe and environmentally-friendly method to exploit natural gas hydrates (“hydrate”) by using flue gas (mainly including CO2 and N2) from electric power plants. So far, however, its energy consumption and energy efficiency has not been investigated thoroughly. In this paper, the process to exploit hydrates from flue gas was established. Firstly, flue gas is injected into hydrate reservoirs after it is pressurized. The hydrates in reservoirs partially experience thermal decomposition while the rest is replaced with flue gas, so CH4CO2N2 mixture is formed. Secondly, the concentrated CH4CO2 mixture is got after N2 is separated and removed by using membrane component. And thirdly, the CH4CO2 mixture is delivered to the original electric power plant. This process was simulated by using the software Aspen Plus to analyze the production/injection ratio in the process of flue gas replacement under different injection pressures, the methane replacement ratio, and the energy consumption and energy efficiency in the whole process. It is indicated that the energy in the process of hydrate exploitation from flue gas is mainly consumed at the pressurized injection stage, and the injection pressure increase correspondingly results in the increase of energy consumption at pressurization and membrane separation stages, and to some extent improves the recovery ratio of pressure energy. Besides, when the injection pressure is 5–16 MPa, the production/injection ratio in the process of flue gas replacement is 0.03–0.26, the methane replacement ratio is 19.9–56.2%, the unit energy consumption in the whole process is 2.15–1.05 (kW·h)/kgCH4, and the energy return on investment (EROI) is 7.2–14.7. It is concluded that the energy efficiency of hydrate exploitation from flue gas can be effectively improved by increasing the injection pressure in the range of 5–10 MPa.