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Abstract Purpose This study aimed to identify the risk factors associated with ampullary duodenal carcinoma (a-DC) and develop a clinical model to dynamically and accurately predict the risk of lymph node metastasis (LNM) in a-DC patients. Methods Data from 4077 patients (2004–2020) were extracted from the Surveillance, Epidemiology, and End Results database to form a training cohort, while 173 cases (2010–2020) from Zhejiang Provincial People’s Hospital in China were used as an external validation cohort. A reliable LASSO-logistic method was employed to identify independent risk factors for a-DC LNM, and a nomogram was developed based on these factors to assess the risk of a-DC LNM. The nomogram was evaluated using the Akaike information criterion, misclassification error, area under the curve, and likelihood ratio test. Finally, the nomogram’s accuracy and generalizability were externally validated.. Results After screening using LASSO and logistic regression four variables were identified as independent risk factors for a-DC LNM: sex (P

Accurate estimation of natural gas consumption plays a crucial role in energy planning, economic stability, environmental protection, and investment decisions. Despite numerous predictive studies related to natural gas consumption, most of these studies focus on univariate prediction tasks, lacking a reasonable and efficient multivariate prediction approach. To obtain precise forecasting results, this paper constructs a new adaptive grey multivariate prediction model called AGMPM(r,N) based on the fractional-order accumulation operation and grey system theory. It is found that AGMPM(r,N) can degenerate into some grey multivariable prediction models by replacing its own hyperparameters, which reflects its uniformity. In addition, the new model is unbiased for some special time series. In particular, the grey wolf optimizer is used to facilitate the model solution process. To validate the effectiveness of AGMPM(r,N), AGMPM(r,N) and 27 competing algorithms (9 natural gas consumption prediction methods, 10 multivariate prediction models, 7 machine learning algorithms and a statistical predictive model) are used to study the natural gas consumption in China. In addition, ablation experiments are executed. The results of experimental analysis show that the MAPE and MAE of AGMPM(r,N) are 2.795% and 89.880, respectively, which are superior to all competing methods and ablation models.

Targeting checkpoints for immune cell activation has been acknowledged known as one of the most effective way to activate anti-tumor immune responses. Among them, drugs targeting cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) are approved for clinical treatment though several more are in advanced stages of development, which demonstrated durable response rates and manageable safety profile. However, its therapy efficacy is unsatisfactory in pancreatic cancer (PC), which can be limited by the overall condition of patients, the pathological type of PC, the expression level of tumor related genes, etc. To improve clinical efficiency, various researches have been conducted, and the efficacy of combination therapy showed significantly improvement compared to monotherapy. This review analyzed current strategies based on anti-CTLA-4 combination immunotherapy, providing totally new idea for future research.

Abstract Background Triple-negative breast cancer (TNBC) possesses special biological behavior and clinicopathological characteristics, which is highly invasive and propensity to metastasize to lymph nodes, leading to a worse prognosis than other types of breast cancer. Thus, the development of an effective therapeutic method is significant to improve the survival rate of TNBC patients. Results In this work, a liposome-based theranostic nanosystem (ILA@Lip) was successfully prepared by simultaneously encapsulating IR 780 as the photosensitizer and lenvatinib as an anti-angiogenic agent, together with banoxantrone (AQ4N) molecule as the hypoxia-activated prodrug. The ILA@Lip can be applied for the near-infrared (NIR) fluorescence diagnostic imaging of TNBC and its lymph node metastasis for multimodal therapy. Lenvatinib in ILA@Lip can inhibit angiogenesis by cutting oxygen supply, thereby leading to enhanced hypoxia levels. Meanwhile, large amounts of reactive oxygen species (ROS) were produced while IR 780 was irradiated by an 808 nm laser, which also rapidly exhausted oxygen in tumor cells to worsen tumor hypoxia. Through creating an extremely hypoxic in TNBC, the conversion of non-toxic AQ4N to toxic AQ4 was much more efficiency for hypoxia-activated chemotherapy. Cytotoxicity assay of ILA@Lip indicated excellent biocompatibility with normal cells and tissues, but showed high toxicity in hypoxic breast cancer cells. Also, the in vivo tumors treated by the ILA@Lip with laser irradiation were admirably suppressed in both subcutaneous tumor model and orthotopic tumor models. Conclusion Utilizing ILA@Lip is a profound strategy to create an extremely hypoxic tumor microenvironment for higher therapeutic efficacy of hypoxia-activated chemotherapy, which realized collective suppression of tumor growth and has promising potential for clinical translation.

Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn) is a crop of significant interest due to its nutritional value and resilience to drought conditions. However, drought, particularly following flowering, is a major factor contributing to yield reduction. This research employed two distinct Tartary buckwheat genotypes to investigate the effects of post-anthesis drought on growth and physicochemical characteristics. The study aimed to elucidate the response of Tartary buckwheat to drought stress. The findings indicated that post-anthesis drought adversely impacted the growth, morphology, and biomass accumulation of Tartary buckwheat. Drought stress enhanced the maximum photosynthetic capacity (Fv/Fm) and light protection ability (NPQ) of the ‘Xiqiao-2’ genotype. In response to drought stress, ‘Dingku-1’ and ‘Xiqiao-2’ maintained osmotic balance by accumulating soluble sugars and proline, respectively. Notably, ‘Xiqiao-2’ exhibited elevated levels of flavonoids and polyphenols in its leaves, which helped mitigate oxidative damage caused by drought. Furthermore, rewatering after a brief drought period significantly improved plant height, stem diameter, and biomass accumulation in ‘Dingku-1’. Overall, ‘Xiqiao-2’ demonstrated greater long-term tolerance to post-anthesis drought, while ‘Dingku-1’ was less adversely affected by short-term post-anthesis drought.

Abstract It is of engineering interest to explore recovered shale gas composition and its effects on total gas production trend over a long-term extraction period. However, there are previous experimental studies mostly focused on short term development for small scaled cores, which is less convincing to mimic reservoir-scaled shale production process. In addition, the previous production models mostly failed to account for comprehensive gas nonlinear effects. As a result, in this paper, to illustrate the full-life-cycle production decline phenomenon for shale gas reservoir, dynamic physical simulation was performed for more than 3433 days to simulate shale gas transport out of the formations over a relatively long production period. Moreover, a five-region seepage mathematical model was then developed and was subsequently validated by the experimental results and shale well production data. Our findings show that for physical simulation, both the pressure and production declined steadily at an annual rate of less than 5%, and 67% of the total gas in the core was recovered. These test data supported earlier finding that shale gas is of low flow ability and slow pressure decline in the shale matrices. The production model indicated that free gas accounts for the majority of recovered shale gas at the initial stage. Based on a shale gas well example, free gas extraction makes up 90% of produced total gas. The adsorbed gas constitutes a primary gas source during the later stage. Adsorbed gas contributes more than 50% of the gas produced in the seventh year. The 20-year-cumulative adsorbed gas makes up 21% of the EUR for a single shale gas well. The results of this study can provide a reference for optimizing production systems and adjusting development techniques for shale gas wells throughout the combinations of mathematical modeling and experimental approaches.

As an emerging environmental contaminant, perfluorooctane sulfonate (PFOS) has attracted increasing attention. This study investigated the occurrence, partitioning and diffusion behavior, and risk assessment of PFOS in 19 water and sediment samples collected from the Yangtze Estuary and coastal waters in March 2022. The concentration of PFOS is 0.053–0.95 ng L−1 in water and 0.031–0.18 ng g−1 (dw) in sediments, demonstrating a transparent concentration gradient from inshore to offshore sites. The fugacity fraction model results showed that, except for a few sites, the diffusion trend of PFOS was from sediment into the water. Correlation and response coefficient (RC) analyses revealed a significant relationship between sediment organic carbon (TOC) and PFOS partitioning. According to the sediments-water partitioning coefficient Kd, in estuarine areas, seawater salinity tended to allocate PFOS to sediments. Ecological risk assessment findings revealed that PFOS posed a low to moderate risk in sediment rather than a problem in water.

Purpose: The purpose of this prospective observational study was to investigate the relationship between pretreatment neutrophil-to-lymphocyte ratio (NLR) and posttreatment early tumor shrinkage (ETS), and clinical outcomes in patients with unresectable hepatocellular carcinoma (uHCC) who received lenvatinib, programmed death-1 inhibitors plus transcatheter arterial chemoembolization. Patients and Methods: A total of 63 uHCC patients were treated with this triple combination. Multivariate analyses to determine the independent factors associated with overall survival (OS) were employed. The link between NLR and clinical results was further analyzed. Furthermore, the predictive value of combining NLR with ETS should be investigated to stratify patients receiving treatment for survival benefits. Results: Progression-free survival and OS were 9.8 and 23.0 months, respectively, with a median follow-up of 20.8 months. On a multivariate analysis of OS, NLR was the only independent prognostic factor. Patients with NLR low (NLR

Abstract Peridynamics provides a new model and method for describing material failure and fracture development. In this study, a three‐dimensional peridynamic fluid–solid coupling model of hydraulic fracture propagation was established. The model considered the effective stress and transverse isotropic characteristics of shale and was used to simulate the propagation of the hydraulic fracturing of bedding shale. The damage evolution influence on the fracture propagation behavior, as well as the interactions between the fractures and bedding, were investigated through a simulation. The damage evolution had discontinuous characteristics. In addition to the incomplete damage zone adjacent to the complete damage zone, there were nonadjacent and incomplete damage zones. The fracture and propagation of hydraulic fractures followed the same trends of damage evolution. Moreover, the simulation and related experimental results confirmed the existence of a large amount of mesodamage in the region far from the fracture, and the concept of “remote damage” in hydraulic fracturing was proposed. Finally, the damage evolution of the propagating fractures and bedding was simulated. The simulation showed that bedding hinders the propagation of main fractures in the height direction but promotes the complexity of fracture propagation. Overall, this study provides a new theoretical understanding and research ideas for an in‐depth understanding of hydraulic fracture geometry and the accurate calculation of Stimulated Reservoir Volume.

Abstract Due to strong stress sensitivity resulted from unconventional tight formationsit is of practical interest to formulate a reasonable pressure drawdown plan to improve gas extraction recovery. The impact of water-shale interactions on the reservoir permeability was previously ignored in the managed pressure drawdown optimization. The controlled-pressure production dynamic analysis was mostly conducted using numerical simulation, lack of rigorous theoretical support. Hence in this paper, a theoretical production prediction model was proposed and verified with HIS RTA 2015by incorporating multiple pressure drawdown mechanisms and various non-linear gas flow process. The on-site production effects dominated by two different pressure drop methods was further compared, indicating that compared to depressurization production, the production reversion can occur in the controlled pressure production process and the EUR of single well can be increased by about 30% under the control of managed pressure drawdown approach. Finally, the pressure drawdown optimization strategy was carried out on the field test from the both production effect and economic benefits, which demonstrated that the best economic solution can generally be obtained in the early stage of production. The research results can be closely linked to the on-site production practice of shale gas wells, providing insights into designing optimized production strategy scheme.

To efficiently develop deep shale gas in southern Sichuan Basin, under the guidance of “extreme utilization” theory, a basic idea and solutions for deep shale gas development are put forward and applied in practice. In view of multiple influencing factors of shale gas development, low single-well production and marginal profit of wells in this region, the basic idea is to establish “transparent geological body” of the block in concern, evaluate the factors affecting shale gas development through integrated geological-engineering research and optimize the shale gas development of wells in their whole life cycle to balance the relationship between production objectives and development costs. The solutions are as follows: (1) calculate the gold target index and pinpoint the location of horizontal well drilling target, and shale reservoirs are depicted accurately by geophysical and other means to build underground transparent geological body; (2) optimize the drilling and completion process, improve the adaptability of key tools by cooling, reducing density and optimizing the performance of drilling fluid, the “man-made gas reservoir” is built by comprehensively considering the characteristics of in-situ stress and fractures after the development well is drilled; (3) through efficient management, establishment of learning curve and optimization of drainage and production regime, the development quality and efficiency of the well are improved across its whole life cycle, to fulfil “extreme utilization” development of shale gas. The practice shows that the estimated ultimate recovery of single wells in southern Sichuan Basin increase by 10%-20% than last year.

Abstract The remarkable prediction of petroleum consumption is of significance for energy scheduling and economic development. Considering the uncertainty and volatility of petroleum system, this paper presents a nonlinear grey Bernoulli model with combined fractional accumulated generation operator to forecast China’s petroleum consumption and terminal consumption. The newly designed model introduces a combined fractional accumulated generation operator by incorporating the traditional fractional accumulation and conformable fractional accumulation; compared to the old accumulation, the newly optimized accumulation can enhance flexible ability to excavate the development patterns of time-series. In addition, to further improve the prediction performance of the new model, marine predation algorithm is applied to determine the optimal emerging coefficients such as fractional accumulation order. Furthermore, the proposed model is verified by a numerical example of coal consumption; and this newly established model is applied to predict China’s petroleum consumption and terminal consumption. Our tests suggest that the designed ONGBM(1,1,k,c) model outperforms the other benchmark models. Finally, we predict China’s petroleum consumption in the following years with the aid of the optimized model. According to the forecasts of this paper, some suggestions are provided for policy-makers in the relevant sectors.

Accurate estimation of Reference Evapotranspiration (ET0) is important for efficient management and conservation of irrigation water. Existing methods of ET0 rate determination are complex for application at the farmer level. Apart from standard methods of ET0 determination, many data-driven soft computing approaches were also proposed to determine the ET0 with limited data set. We proposed a temperature and humidity-based ML approach for ET0 rate determination on directly sensed environmental conditions of the crop field. Crop field environmental conditions for (ET0) rate determination are sensed by the proposed Internet of Things (IoT) architecture. Crop field environmental conditions from the year 2015 to 2021 in Pakistan are used for the training and testing of the proposed model. Gaussian Naive Bayes (GNB), Support Vector Machine (SVM), k-Nearest Neighbours (KNN), and Artificial Neural Network (ANN) based models are compared for performance. Crop fields directly sensed temperature and humidity pass to the model to train and predict the ET0-rate of crop fields. The 10-fold cross-validation technique is applied for the evaluation of the proposed approach. The accuracy of the proposed solution for the ET0 rate is compared against the Food and Agriculture Organization (FAO) recommended Penman-Monteith method for ET0 rate determination. As concerned of the ML-based models the KNN model is more accurate as compared to SVM,GNB and ANN models with 92% accuracy. The KNN model of ET0 is more efficient in reducing the Root Mean Squared Errors (RMSE) by 16% and Mean Absolute Errors (MAE) by 3% against the state of the art approach.

Compared with visceral cancers, breast cancer is epidermal and can be efficiently eliminated by photoacoustic imaging (PAI)-guided cancer therapy. In this study, we developed multifunctional nanoparticles (DMTH NPs) by loading doxorubicin (DOX) into MIL-100, which were modified with tannic acid (TA) and hyaluronic acid (HA) using a simple and convenient method. MIL-100 (Fe) in DMTH NPs allowed for chemodynamic therapy by converting endogenous hydrogen peroxide (H2O2) into •OH through a Fenton-like reaction to assist DOX in killing cancer cells. DMTH NPs had high DOX loading efficiency for chemotherapeutic function and had the ability for photoacoustic imaging (PAI) and photothermal therapy (PTT) after being modified by TA. Specifically, DMTH NPs targeted tumors and had low toxicity in vivo. Ultimately, the released DOX and •OH cooperated in killing MCF-7 cells effectively in vitro. The enhanced and precise breast cancer treatment was achieved using a PAI-guided chemodynamic/chemo/photothermal synergistic therapy under laser irradiation in vivo. Overall, this work presented an innovative strategy for designing multifunctional nanoparticles for effective imaging-guided combination therapies to combat breast cancer.

Summary: Autophagy plays critical roles in the pluripotent stemness of cancer stem cells (CSCs). However, how CSCs maintain the elevated autophagy to support stemness remains elusive. Here, we demonstrate that bladder cancer stem-like cells (BCSLCs) are at slow-cycling state with enhanced autophagy and mitophagy. In these slow-cycling BCSLCs, the DNA replication initiator MCM7 is required for autophagy and stemness. MCM7 knockdown inhibits autophagic flux and reduces the stemness of BCSLCs. MCM7 can facilitate autolysosome formation through binding with dynein to promote autophagic flux. The enhanced autophagy/mitophagy helps BCSLCs to maintain mitochondrial respiration, thus inhibiting AMPK activation. AMPK activation can trigger switch from autophagy to apoptosis, through increasing BCL2/BECLIN1 interaction and inducing P53 accumulation. In summary, we find that MCM7 can promote autophagic flux to support.

Low-resistivity shales are widely developed in the Sichuan Basin. The production of low-resistivity shale gas reservoirs ranges from high to low to none. The existing methods for gas-content prediction cannot accurately predict the gas content of low-resistivity shale. This increases the risk of shale-gas exploration. To prove that the random forest algorithm has apparent advantages in predicting the gas content of low-resistivity shale and reducing the risks associated with shale-gas exploration and development, three prediction methods were selected in this paper to compare their effects. The first method is known as the grey-correlation multiple linear regression method. Low-resistivity shale-gas content logging series were optimized using the grey-correlation approach, and then the low-resistivity shale-gas-content prediction model was established using the multiple linear regression method. The second method we selected was the resistivity method. The improved water-saturation model was used to predict the water saturation of low-resistivity shale, and then the gas content of low-resistivity shale was predicted based on the free-gas content and the adsorbed-gas-content model. The random forest algorithm was the third method we selected. Fourteen logging series were used as input data and the measured gas content was used as supervised data to train the model and to apply the trained model to the gas-content prediction. The findings demonstrated that the grey-correlation multiple regression method had poor accuracy in predicting gas content in low-resistivity shale; The resistivity method accurately predicted water saturation, and the predicted gas content was higher than the actual gas content. Because the random forest algorithm accurately predicted low-resistivity shale-gas content, its use in the Sichuan Basin was advantageous. The selection of a low-resistivity shale-gas-content prediction model was guided by the research findings.

With the growing demand of oil worldwide, heavy oil has increasingly become vital in the world energy market. However, further development of heavy oil reservoirs are limited by regular enhanced oil recovery (EOR) methods. In situ upgrading technology provides potential for the development of heavy oil and bitumen reservoirs. This study reviews three categories of in situ upgrading methods: solvent-based, in situ combustion (ISC), and catalytic. Solvent-based methods, including cyclic solvent injection, vapor extraction, and hybrid processes, have recently received attention and have been progressed in both laboratory and field applications. However, high solvent costs in relation to the low price of heavy oil have continued to limit the field applications of these techniques. ISC, which may have the potential to develop particularly harsh reservoirs with extremely viscous crude oil, involves complex reaction mechanisms and consists of three main steps: oxidation, combustion, and gas flooding. Yet, complex operating conditions and a low success rate have restricted its application. Catalytic methods, which have demonstrated the potential to refine and upgrade crude oil in a more economic and environmentally friendly way, are often accompanied by conventional thermal EOR methods, such as steam flooding and ISC, and involve a series of hydroprocessing or hydrotreating reactions, such as hydrocracking, hydrodesulfurization, hydrodenitrogenation, hydrodeoxygenation, and hydrodemetallization. However, the high cost and complexity of the reaction mechanisms have limited their applications.

Exploring renewable energy is beneficial for ameliorating the energy crisis and reducing environmental emissions. The hybrid utilization of solar and geothermal energies is an effective way to improve the existing energy consumption structure dominated by fossil energy. This paper proposes a novel power generation system composed of a topping recompression supercritical carbon dioxide (sCO2) Brayton cycle and a bottom organic flash cycle (OFC) driven by the hybrid solar-geothermal energies. The sCO2 Brayton cycle is driven by the heat from the solar tower system, and the OFC is driven by a part of the heat from CO2 in the sCO2 Brayton cycle and another part of the heat from the geothermal water. The corresponding energy and exergy analyses of the proposed combined system are presented. The effects of the five main parameters on the system thermodynamic performance are carried out, which are direct radiation intensity, concentration ratio, sCO2 pressure ratio, preheater terminal temperature difference, and flash temperature. Results show that the OFC with R245ca has the highest exergy efficiency among the different four fluids. The energy efficiency and exergy efficiency of the total system are 26.03% and 33.38%, respectively, since the energy losses exist in the heliostat field and central receivers. There observes that through the parametric study the parameters of direct radiation intensity and concentration ratio are larger causing better system thermodynamic performance. Through the thermodynamic analysis, there observes the power cycle subsystem has the largest energy loss, while the central receiver possesses the highest among other subsystems.

Self-oscillating systems that enable autonomous motions driven by a constant stimulus find applications in numerous fields but these systems are plagued with problems that restrict their practical applicability. Here, the authors create a photoactive self-winding fiber actuator that possesses a broad range of oscillation modes, controllable evolution between diverse modes, and loading capability.

The search for and characterization of new lipases with excellent properties has always been urgent and is of great importance to meet industrial needs. In this study, a new lipase, lipB, from Pseudomonas fluorescens SBW25, belonging to the lipase subfamily I.3, was cloned and expressed in Bacillus subtilis WB800N. Enzymatic properties studies of recombinant LipB found that it exhibited the highest activity towards p-nitrophenyl caprylate at 40 °C and pH 8.0, retaining 73% of its original activity after incubation at 70 °C for 6 h. In addition, Ca2+, Mg2+, and Ba2+ strongly enhanced the activity of LipB, while Cu2+, Zn2+, Mn2+, and CTAB showed an inhibiting effect. The LipB also displayed noticeable tolerance to organic solvents, especially acetonitrile, isopropanol, acetone, and DMSO. Moreover, LipB was applied to the enrichment of polyunsaturated fatty acids from fish oil. After hydrolyzing for 24 h, it could increase the contents of polyunsaturated fatty acids from 43.16% to 72.18%, consisting of 5.75% eicosapentaenoic acid, 19.57% docosapentaenoic acid, and 46.86% docosahexaenoic acid, respectively. The properties of LipB render it great potential in industrial applications, especially in health food production.

Huangjiu is one of the oldest alcoholic beverages in the world. It is usually made by fermenting grains, and Qu is used as a saccharifying and fermenting agent. In this study, we identified differential carbonyl compounds in Huangjiu with varying sugar contents from different regions. First, we developed and validated a detection method for volatile carbonyl compounds in Huangjiu, and for optimal extraction, 5 mL of Huangjiu and 1.3 g/L of O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) were incubated at 45 °C for 5 min before extracting the volatile carbonyl compounds at 45 °C for 35 min. Second, the targeted quantitative analysis of 50 carbonyl compounds in Huangjiu showed high levels of Strecker aldehydes and furans. Finally, orthogonal projections to latent structures discriminant analysis (OPLS-DA) was used to differentiate between Huangjiu with different sugar contents, raw materials, and region of origin. A total of 19 differential carbonyl compounds (VIP > 1, p < 0.05) were found in Huangjiu with different sugar contents (semidry and semisweet Huangjiu), and 20 differential carbonyl compounds (VIP > 1, p < 0.05) were found in different raw materials for Huangjiu production (rice and nonrice Huangjiu). A total of twenty-two and eight differential carbonyl compounds, with VIP > 1 and p < 0.05, were identified in semidry and semisweet Huangjiu from different regions (Zhejiang, Jiangsu, Shanghai, and Fujian), respectively.

So far, how imbibition effect changes the occurrence state of shale gas has not been quantitatively understood, and the law of gas–water dynamic displacement caused by the retention of abundant fracturing fluid in a shale reservoir has not been determined clearly. In this paper, a gas–water displacement experiment was performed to simulate the change in the water content of shale near the wellbore after hydraulic fracturing. Then, based on the low field nuclear magnetic resonance spectrum analysis technique of hydrogen-bearing fluid (1H-NMR), the occurrence state of methane in shale reservoirs was dynamically monitored and methane volume in different occurrence states was calculated. Finally, the law of imbibition effect on the occurrence state of shale gas was studied. And the following research results were obtained. First, the process of shale saturation with methane is divided into adsorption-dominant phase and pore-filling phase. And adsorption and pressure gradient play a role simultaneously in the process of shale saturation with methane. Second, in the early stage of the process of shale saturation with methane, priority is given to saturated adsorbed gas, and free methane exists in shale pores as an intermediate state in which the external methane is converted to the adsorbed methane. After the adsorbed gas reaches the saturated state, methane fills shale pores under the pressure gradient until the pressure inside and outside the pores is balanced. Third, imbibition effect leads to the occurrence of gas–water displacement in shale. The adsorbed methane is partially desorbed into free methane, and the proportion of adsorbed gas is reduced. After 80 h' imbibition, the proportion of adsorbed gas is reduced from 63.58% to 45.87%. The increase of free gas volume results in the rise of shale pore pressure. And at the same time, water occupies partial pore volume to compress the storage space of free gas and expel some free gas out of shale pores. In this way, the gas bearing property of the reservoir is deteriorated, and the gas content of the shale sample is reduced to 7.34 mL/g from 7.91 mL/g which is the value before the beginning of imbibition. Fourth, the retention of abundant fracturing fluid in the process of hydraulic fracturing makes the shale reservoir near the wellbore in the state of rich water, the gas–water displacement induced by imbibition effect increases the volume of free methane in the external space (such as shale pore and wellbore), and the increase of pore pressure leads to the rise of the formation pressure, which is beneficial to the exploitation of shale gas to a certain extent.

When floating at the air water interface, the shape of objects determines their capillary menisci and mutual interaction. Hu et al. show how dynamically changing shapes of liquid-crystal polymer actuators can be used to achieve optically controlled and reconfigurable assembly.

Background: Eye tracking technology is receiving increased attention in the field of virtual reality. Specifically, future gaze prediction is crucial in pre-computation for many applications such as gaze-contingent rendering, advertisement placement, and content-based design. To explore future gaze prediction, it is necessary to analyze the temporal continuity of visual attention in immersive virtual reality. Methods: In this paper, the concept of temporal continuity of visual attention is presented. Subsequently, an autocorrelation function method is proposed to evaluate the temporal continuity. Thereafter, the temporal continuity is analyzed in both free-viewing and task-oriented conditions. Results: Specifically, in free-viewing conditions, the analysis of a free-viewing gaze dataset indicates that the temporal continuity performs well only within a short time interval. A task-oriented game scene condition was created and conducted to collect users' gaze data. An analysis of the collected gaze data finds the temporal continuity has a similar performance with that of the free-viewing conditions. Temporal continuity can be applied to future gaze prediction and if it is good, users' current gaze positions can be directly utilized to predict their gaze positions in the future. Conclusions: The current gaze's future prediction performances are further evaluated in both free-viewing and task-oriented conditions and discover that the current gaze can be efficiently applied to the task of short-term future gaze prediction. The task of long-term gaze prediction still remains to be explored.

Shale gas reservoirs have pores of various sizes, in which gas flows in different patterns. The coexistence of multiple gas flow patterns is common. In order to quantitatively characterize the flow pattern in the process of shale gas depletion development, a physical simulation experiment of shale gas depletion development was designed, and a high-pressure on-line NMR analysis method of gas flow pattern in this process was proposed. The signal amplitudes of methane in pores of various sizes at different pressure levels were calculated according to the conversion relationship between the NMR T2 relaxation time and pore radius, and then, the flow patterns of methane in pores of various sizes under different pore pressure conditions were analyzed as per the flow pattern determination criteria. It is found that there are three flow patterns in the process of shale gas depletion development, i.e., continuous medium flow, slip flow, and transitional flow, which account for 73.5%, 25.8%, and 0.7% of total gas flow, respectively. When the pore pressure is high, the continuous medium flow is dominant. With the gas production in shale reservoir, the pore pressure decreases, the Knudsen number increases, and the pore size range of slip flow zone and transitional flow zone expands. When the reservoir pressure is higher than the critical desorption pressure, the adsorbed gas is not desorbed intensively, and the produced gas is mainly free gas. When the reservoir pressure is lower than the critical desorption pressure, the adsorbed gas is gradually desorbed, and the proportion of desorbed gas in the produced gas gradually increases.

Archie’s parameters are substantial to be investigated in the evaluation of water saturation. Many researchers adhered to the opinion that Archie’s equation can still be applied to water saturation calculation in shale if the accuracy of relative parameters could be improved. External conditions, such as temperature, confining pressure, water salinity, wettability, and displacement, may influence the determination of Archie’s parameters. The aim of the study is to investigate the effect of salinity on Archie’s parameters and their correlation with mineral composition and pore structure. The mineral contents and petrophysical properties were firstly acquired through X-ray diffraction (XRD) and basic measurements. Rock-electric experiments under different salinity were conducted on deep shale samples taken from Longmaxi (LMX) Formation in Luzhou (LZ). The results indicate that Archie’s parameters of “a,” “b,” “m,” and “n” under actual brine salinity are assigned to 1.47, 1, 1.26, and 1.6, respectively. Our cementation factor is lower than that in other studies including (shaly) sandstones, carbonates, and shales, probably due to the extremely low porosity in study area. Salinity has a positive effect on cementation factor (m) and saturation exponent (n), suggesting the traditional assignment to Archie’s parameters is inappropriate. It was concluded that the complicated pore structure and high porosity mainly associated with clay mineral may trigger the increased cementation factor. Further mathematical derivations confirmed that the rock resistivity is inextricable from pore system and establish a physical model. The paper provides a solid evidence base for further understanding and evaluation of water saturation in unconventional shale reservoirs, more significantly, innovatively unveils the research into Archie formula in deep shale reservoirs of southern Sichuan basin.

To obtain a Johnson–Cook model of 15-5 PH steel formed by selective laser melting (SLM), and to determine the difference between the forging process, in this work, mechanical testing, penetration testing and numerical simulations were used to study 15-5 PH steel formed by SLM and forging. Finally, the Johnson–Cook model parameters and failure parameters of the 15-5 PH steel formed by SLM and forging were obtained. We found that the SLM process was beneficial for refining the grain size of 15-5 PH steel and for improving the mechanical properties of 15-5 PH steel, where the yield strength of its specimens increased by 13.1% compared with the forged specimens. The error between the numerical simulations and penetration tests was less than 10%, which verified the validity of the numerical model parameters. It was also found that the penetration ability and abrasion resistance of the SLM-shaped projectiles were slightly superior to those of the forged projectiles.

The occurrence mechanism of methane is very important as evaluating the gas-bearing properties of marine shale reservoirs, and the evaluation of the development effect of shale gas wells need to focus on the migration mechanism of methane. In this study, LTNA technology and NMR technology were used to analyze the pores and methane of shale. The results show that inorganic pores have better connectivity, larger pore size, and micro–nano cracks between pores compared to organic pores. Most of the pores in shale are micropores and mesopores, which provide most of the specific surface area, but the contribution of macropores to pore volume cannot be ignored. Adsorbed gas volume depends on the pore surface area and gas pressure, while free gas volume depends on pore volume and gas pressure. The pore structure of micropores and mesopores is complex, and the specific surface area is large. The dispersion force between pore surface molecules and methane molecules is firm, which makes the pore wall an ideal enrichment space for adsorbed gas. Macropores have larger pore volumes and can store more free gas. In the process of gas well development, free gas is first discharged from pores under the action of the pressure gradient. As the pore pressure is lower than the critical desorption pressure, adsorbed gas begins to desorb in large quantities. It should be noted that the desorption process of adsorbed gas is slow and persistent, which makes it impossible for gas wells to achieve higher recovery in a shorter production cycle. Therefore, improving the recovery rate of adsorbed gas is the key to future research on shale gas development effects. This study is helpful in clarifying the occurrence and migration mechanism of methane in marine shale reservoirs and guiding the development of gas wells.

The ultra-low porosity and permeability, as well as complex occurrence and transport state of shale reservoir make it possess special L-type production characteristic curve and complicated shale gas flow mechanism. To solve the difficulty of collecting complete production data due to short production time and operation discontinuity, a full-diameter core physical simulation experiment on the full lifecycle production process of shale gas well depletion is conducted with the purpose of obtaining many important production data including complete pressure and daily gas output in the simulated production process of shale gas well. The experimental results show the production characteristic from simulation is consistent with those from gas well. Based on the simulation data, the critical desorption pressure (12 MPa) of core, free gas production (3820.8 mL), adsorbed gas production (2151.2 mL), the proportion of the daily gas production between free and absorbed gas under different time and formation pressure, as well as the production time and final recovery rate corresponding to abandoned pressure, can be determined accurately. Numerical inversion is carried out to calculate the production performance curve of shale gas well and predict the development effect of gas well based on well testing and similarity analysis of the dimensionless time between core experiment and gas well production. Finally, the permeability and the fracturing effect (fracture network density) as the keys to the effective development of shale gas reservoirs are proposed. The permeability is the fundamental factor and the fracturing technology is the major means. Keywords: Shale gas well, Full lifecycle, Physical simulation experiment, Numerical inversion, Similarity theory, Permeability, Fracturing effect

In this paper, shale samples of Lower Silurian Longmaxi Fm, taken from the Changning–Weiyuan area in the Sichuan Basin, were selected to figure out the influence of reservoir primary water on the adsorption laws and the flow capacity of shale gas. Experimental samples with different water saturations were prepared using the adsorption equilibrium method. Then, high-pressure isothermal adsorption experiments were carried out, and the isothermal adsorption effects and mechanisms of shale under different water saturations were discussed. Finally, the flow capacity of shale gas under different water saturations was tested using the independently developed steady-state flow test device. And the following research results were obtained. First, the presence of primary water in micron–nanometer pores of shale reservoirs reduces the adsorption capacity of shale. When the water saturation is 40%, the simulated total gas content is 18% lower than that in the conventional calculation result. Second, the apparent shale permeability is a function of pressure. Due to the effect of Knudsen diffusion, the apparent shale permeability increases significantly with the decrease of pressure under low pressure. When the average pressure is 5 MPa and the water saturation reaches 50%, the apparent shale permeability is about 70% lower than that of a dry sample. Third, when the water saturation is lower than the critical value, water is mainly presented as non-movable water in micropores and mesopores, and it has less effect on the flow capacity of shale gas. When the water saturation is greater than the critical value, the lodging point of water is changed, resulting in significant reduction of the shale gas flow capacity. It is concluded that an accurate understanding of the original water saturation and critical water saturation of shale reservoirs helps to calculate shale gas reserves accurately and predict gas well production rate rationally. Keywords: Shale gas, Reservoir, Water saturation, Isothermal adsorption, State of occurrence, Flow capacity, Reserves, Gas production rate

The occurrence and flow of shale gas are substantially impacted by nanopore structures. The fractal dimension provides a new way to explore the pore structures of shale reservoirs. In this study, eight deep shale samples from Longmaxi Formation to Wufeng Formation in Southern Sichuan were selected to perform a series of analysis tests, which consisted of small-angle neutron scattering, low-pressure nitrogen adsorption, XRD diffraction, and large-scale scanning electron microscopy splicing. The elements that influence the shale fractal dimension were discussed from two levels of mineral composition and pore structures, and the relationship between the mass fractal dimension and surface fractal dimension was focused on during a comparative analysis. The results revealed that the deep shale samples both had mass fractal characteristics and surface fractal characteristics. The mass fractal dimension ranged from 2.499 to 2.991, whereas the surface fractal dimension ranged from 2.814 to 2.831. The mass fractal dimension was negatively correlated with the surface fractal dimension. The mass fractal dimension and the surface fractal dimension are controlled by organic matter pores, and their development degree significantly affects the fractal dimension. The mass fractal dimension increases with the decrease of a specific surface area and pore volume and increases with the increase of the average pore diameter. The permeability and surface fractal dimension are negatively correlated, but no significant correlation exists between the permeability and mass fractal dimension, and the internal reason is the dual control effect of organic matter on shale pores. This study comprehensively analyses the mass fractal characteristics and surface fractal characteristics, which helps in a better understanding of the pore structure and development characteristics of shale gas reservoirs.

Learning the conditional probability table (CPT) parameters of Bayesian networks (BNs) is a key challenge in real-world decision support applications, especially when there are limited data available. The traditional approach to this challenge is introducing domain knowledge/expert judgments that are encoded as qualitative parameter constraints. In this paper, we focus on multiplicative synergistic constraints. The negative multiplicative synergy constraint and positive multiplicative synergy constraint in this paper are symmetric. In order to integrate multiplicative synergistic constraints into the learning process of Bayesian Network parameters, we propose four methods to deal with the multiplicative synergistic constraints based on the idea of classical isotonic regression algorithm. The four methods are simulated by using the lawn moist model and Asia network, and we compared them with the maximum likelihood estimation (MLE) algorithm. Simulation results show that the proposed methods are superior to the MLE algorithm in the accuracy of parameter learning, which can improve the results of the MLE algorithm to obtain more accurate estimators of the parameters. The proposed methods can reduce the dependence of parameter learning on expert experiences. Combining these constraint methods with Bayesian estimation can improve the accuracy of parameter learning under small sample conditions.

Internet of Things (IoT) and Big Data technologies are becoming increasingly significant parts of national defense and the military, as well as in the civilian usage. The proper deployment of large-scale wireless sensor network (WSN) provides the foundation for these advanced technologies. Based on the Fruchterman–Reingold graph layout, we propose the Fruchterman–Reingold Hexagon (FR-HEX) algorithm for the deployment of WSNs. By allocating edges of hexagonal topology to sensor nodes, the network forms hexagonal network topology. A comprehensive evaluation of 50 simulations is conducted, which utilizes three evaluation metrics: average moving distance, pair correlation diversion (PCD), and system coverage rate. The FR-HEX algorithm performs consistently, the WSN topologies are properly regulated, the PCD values are below 0.05, and the WSN system coverage rate reaches 94%. Simulations involving obstacles and failed nodes are carried out to explore the practical applicability of the FR-HEX algorithm. In general, the FR-HEX algorithm can take full advantage of sensors’ hardware capabilities in the deployment. It may be a viable option for some IoT and Big Data applications in the near future.

Grey prediction models have been widely used in various fields of society due to their high prediction accuracy; accordingly, there exists a vast majority of grey models for equidistant sequences; however, limited research is focusing on nonequidistant sequence. The development of nonequidistant grey prediction models is very slow due to their complex modeling mechanism. In order to further expand the grey system theory, a new nonequidistant grey prediction model is established in this paper. To further improve the prediction accuracy of the NEGM (1, 1, t2) model, the background values of the improved nonequidistant grey model are optimized based on Simpson formula, which is abbreviated as INEGM (1, 1, t2). Meanwhile, to verify the validity of the proposed model, this model is applied in two real-world cases in comparison with three other benchmark models, and the modeling results are evaluated through several commonly used indicators. The results of two cases show that the INEGM (1, 1, t2) model has the best prediction performance among these competitive models.

Adsorbed gas and free gas both exist in shale reservoirs simultaneously due to the unique nanoscale pore structure, resulting in the complex flow mechanism of gas in the reservoir during the development process. The dynamic performance analysis of shale reservoirs has mostly been conducted by the numerical simulation and theoretical model, while the physical simulation method for relevant research is seen rarely in the literature. Thus, in this paper, an experiment system was designed to simulate the degraded development experiments of shale, coal, and tight sandstone to reveal the output law of gas in different occurrence states of shale reservoirs and clarify the pressure propagation rules of different reservoirs, and then, adsorption gas and free gas production laws were studied by theoretical models. Research indicated the following: (1) The gas occurrence state is the main factor that causes the difference of the pressure drop rate and gas production law of shale, coal, and tight sandstone. During the early stage of the development of shale gas, the free gas is mainly produced; the final contribution of free gas production can reach more than 90%. (2) The static desorption and dynamic experiments confirm that the critical desorption pressure of adsorbed gas is generally between 12 and 15 MPa. When the gas reservoir pressure is lower than the critical desorption pressure in shale and coal formation, desorption occurs. Due to the slow propagation of shale matrix pressure, desorption of adsorbed gas occurs mainly in the low-pressure region close to the fracture surface. (3) The material balance theory of closed gas reservoirs and the one-dimensional flow model of shale gas have subsequently validated the production performance law of adsorbed gas and free gas by the physical simulation. Therefore, in the practical development of shale gas reservoirs, it is recommended to shorten the matrix supply distance, reduce the pressure in the fracture, increase the effective pressure gradient, and enhance the potential utilization of adsorbed gas as soon as possible to increase the ultimate recovery. The findings of this study can help for a better understanding of the shale reservoir utilization law so as to provide a reference for production optimization and development plan formulation of the shale gas reservoirs.

The shale gas productivity model based on shale gas nonlinear seepage mechanism is an effective way to reasonably predict productivity. The incomplete gas nonlinear effects considered in the current production prediction models can lead to inaccurate production prediction. Based on the conventional five-zone compound flow model, comprehensive gas nonlinearities were considered in the improved compound linear flow model proposed in the paper and a semianalytical solution for productivity was obtained. The reliability of the productivity model was verified by the field data, and then, the 20-year production performance analysis of the gas well was studied. Ultimately, the key influencing factors of the fracture control stage and matrix control stage have been analyzed. Research indicated the following: (1) the EUR predicted by the productivity model is higher than the EUR that the comprehensive nonlinear effects are not considered, which demonstrated that the various nonlinear effects cannot be neglected during the production prediction to ensure the greater calculation accuracy; (2) during the early production stage of shale reservoir, the adsorbed gas is basically not recovered, and the cumulative adsorption contribution rate does not exceed 10%. The final adsorption gas contribution rate is 23.28%, and the annual adsorption rate can exceed 50% in the 20th year, showing that free gas and adsorbed gas are, respectively, important sources of the early stage of production and long-term stable production; (3) the widely ranged three-dimensional fracturing reformation of shale reservoirs and reasonable bottom hole pressure in the later matrix development process should be implemented to increase the effective early production of the reservoir and ensure the earlier gas production process of the matrix development. The findings of this study can help for better ensuring the prediction accuracy of the estimated ultimate recovery and understanding the main influencing factors of the dynamic performance of gas wells so as to provide a theoretical reference for production optimization and development plan formulation of the shale gas reservoirs.

The nonhomogeneous grey model has been seen as an effective method for forecasting time series with approximate nonhomogeneous index law, which has been widely used in diverse disciplines on account of its high prediction precision. However, there remains room for improvements. For this, this study presents an improved nonhomogeneous grey model by incorporating the dynamic integral mean value theorem and fractional accumulation simultaneously. In order to promote the efficacy of the optimised model, we apply the whale optimization algorithm (WOA) to ascertain its optimal parameter. In particular, two examples are conducted to validate the superiority of the proposed model in contrast with other benchmarks, and the experimental results show that the mean absolute percentage error of the proposed approach is 808692% and 6.0706%, respectively, indicating the proposed approach performs better than other competing models.

The acidic tumor microenvironment stands as a major obstacle to the efficient elimination of tumor cells. Norcantharidin (NCTD) is a powerful antitumor agent with multiple bioactivities. However, the effect of NCTD under acidic conditions is still unclear. Here, we report that NCTD can efficiently kill bladder cancer (BC) cells in acidic culture, and more intriguingly, NCTD can induce immunogenic cell death (ICD), thereby promoting antitumor immunity. In NCTD-treated BC cells, the surface-exposed calreticulin (ecto-CALR) was significantly increased. Consistently, co-culture with these cells promoted dendritic cell (DC) maturation. The NCTD-induced ICD is autophagy dependent, as autophagy inhibition completely blocked the NCTD-induced ecto-CALR and DC maturation. In addition, the DC showed a distinct maturation phenotype (CD80high CD86low) in acidic culture, as compared to that in physiological pH (CD80 high CD86high). Finally, the NCTD-induced ICD was validated in a mouse model. NCTD treatment significantly increased the tumor-infiltrating T lymphocytes in MB49 bladder cancer mice. Immunizing mice with NCTD-treated MB49 cells significantly increased tumor-free survival as compared to control. These findings demonstrate that NCTD could induce ICD in an acidic environment and suggest the feasibility to combine NCTD with anticancer immunotherapy to treat BC.

It has been reported that diet and nutrition play important roles in the occurrence and development of hepatocellular carcinoma (HCC). In this study, we investigated the potential tumor-promoting mechanisms of a high-fat diet (HFD) in mice with dietondiethylnitrosamine (DEN)-induced hepatocarcinogenesis. HFD significantly decreased the survival rate and induced severe liver dysfunction in DEN-induced mice, as indicated by increased serum glutamic-pyruvic transaminase (ALT), glutamic oxalacetic transaminase (AST), and alkaline phosphatase (ALP) levels and increased liver index, liver nodule count, and γ-glutamyltransferase (γ-GT) activity. Moreover, an increased number of fat droplets and HCCs were found in the livers of the HFD mice, who displayed little collagen in and around the liver cancer groove and the infiltration of large number of inflammatory cells, such as macrophages, compared with the control mice. HFD also significantly increased proliferating cell nuclear antigen (PCNA), nuclear factor-κB (NF-κB), cyclin D1, tumor necrosis factor (TNF), and interleukin-1 (IL-1) expression levels in the liver. In vitro, we found that the inducible nitric oxide synthase (iNOS) percentage increased in macrophages after palmitic acid treatment, as well as the secretion of inflammatory factors and cytokines such as interleukin-6(IL-6), interleukin-10(IL-10), CCL2, Interferon γ (IFN-γ), and TNF. Thus, our results demonstrate that an HFD may promote DEN-induced hepatocarcinogenesis in mice by destroying liver function and enhancing the inflammatory response by recruiting and polarizing macrophages in the liver. This study could therefore provide new insights into the tumor promoting effects of an HFD in HCC.

Pore characteristics are one of the most important elements in the study of shale reservoir properties and are a key parameter for the evaluation of the potential of shale oil and gas resources. Low-temperature nitrogen adsorption is a common laboratory method that is used to characterize the pore structure of shale. However, the effect of shale’s particle size on the experimental results of the nitrogen adsorption of deep shale samples is still unclear. In this paper, using deep shale samples of different mesh sizes from the Luzhou Block as an example, we studied the effect of particle size on the pore structure of deep shale, as characterized by nitrogen adsorption experiments. The results showed that the pore volume of deep shale is mainly distributed in the mesoporous range, with a pore size ranging from 2 to 20 nm. The pore volume, as measured by nitrogen adsorption, increases slowly as the particle size decreases and then it increases rapidly. The particle size of shale has no obvious effect on the measurement of the specific surface area. The fractal dimension of deep shale gradually increases as the particle size of the shale samples increases and the smaller the particle size, the higher the correlation coefficient, R2, of the fractal dimension fitting. In this paper, different recommended sizes are given for selecting suitable particle sizes in nitrogen adsorption experiments on deep shale with different structural parameters, which will increase the accuracy of the study of the pore structure of deep shale.

Shale reservoir heterogeneity is strong, which seriously affects shale gas reservoir evaluation and reserves estimation. The Longmaxi Formation shale of the Luzhou block in southern Sichuan was taken as an example to characterize the pore distribution of shale over the full scale using micro-computed tomography (CT), focusing on ion beam scanning electron microscopy (FIB-SEM) and small-angle neutron scattering (SANS); further, the heterogeneity of the shale pore distribution over the full scale was explored quantitatively within different scales. The results show that shale micropores are dominated by microfractures that are mainly developed along the bedding direction and associated with organic matter, contributing 1.24% of porosity. Shale nanopores are more developed, contributing 3.57–4.72% porosity and have strong heterogeneity locally at the microscale, but the pore distribution characteristics show lateral homogeneity and vertical heterogeneity at the macroscale. In the same layer, the porosity difference is only 0.1% for the sheet samples with 2 cm adjacent to each other. Therefore, in shale core experiments in which parallel samples are needed for comparison, parallel samples should be in the same bedding position. This paper explores the extent of heterogeneity over the full scale of pore distribution from macro to micro, which has important significance for accurately characterizing the pore distribution of shale and further carrying out reservoir evaluation and estimation of reserves.

The high pressure static adsorption curves of shale samples from Silurian Changning-Weiyuan Longmaxi Formation were tested by using high pressure isothermal adsorption equipment. The physical modeling of depletion production was tested on single cores and multi-core series by using self-developed shale gas fluid-solid coupling experiment system. The adsorption and desorption laws were summarized and a high pressure isothermal adsorption model was established. The calculation formula of gas content was corrected, and the producing law of adsorption gas was determined. The study results show that the isothermal adsorption law of the shale reservoir under high pressure was different from the conventional low pressure. The high pressure isothermal adsorption curve had the maximum value in excess adsorption with pressure change, and the corresponding pressure was the critical desorption pressure. The high pressure isothermal curve can be used to evaluate the amount of adsorbed gas and the producing degree of adsorption gas. The high pressure isothermal adsorption model can fit and characterize the high pressure isothermal adsorption law of shale. The modified gas content calculation method can evaluate the gas content and the proportion of adsorbed gas more objectively, and is the theoretical basis of reserve assessment and production decline analysis. The producing degree of adsorption gas is closely related to the pressure, only when the reservoir pressure is lower than the critical desorption pressure, the adsorption gas can be produced effectively. In the process of gas well production, the pressure drop in the near-well area is large, the production of adsorption gas is high; away from the wellbore, the adsorption gas is low in production, or no production. Key words: shale, high pressure isothermal adsorption, excess adsorption, critical desorption pressure, shale gas, adsorption curve

In order to achieve the IOT, in the traditional one-cycle controlled PFC circuit, the system's switching losses considerably increase with the control switching frequency and the system's power, severely affecting the system's efficiency. In order to address this problem, an improved one-cycle hysteresis controlling circuit is proposed in this paper. An improved one-cycle controlled PFC circuit is also proposed to minimize the input current pulsation. The duty ratio of the output-control power switching tube is computed in real-time by computing the rate of rise and fall of the current in the input inductance. The next current sampling point is computed in real-time based on the duty ratio of each switching period. A simulation model and 152VA prototype are established via Matlab, Simulation, and test results of the prototype demonstrate the correctness and feasibility of the proposed one-cycle hysteretic control circuit and the current pulsation minimization algorithm.

The development of shale gas in the United States has made a breakthrough, profoundly changed the pattern of oil and gas supply. It created the “shale gas revolution” on a global scale. Based on the practice of shale gas development in China and abroad, this paper aims to: (1) Summarize 5 basic characteristics, which are shale gas resource distribution, reservoir space, sweet spot area (section), hydrocarbon type and development mode. (2) Divide China shale development into three stages: scientific exploration, technological breakthrough and mature development. The United States is divided into three stages: scientific exploration, technological breakthrough and mature development. The United States is divided into three stages: scientific exploration, technological breakthrough and mature development. (3) Identify 4 challenges in the future development of China shale gas industry. It includes non-marine shale gas potential, core technology and equipment for resource deep than 3500 m, complex surface “factory mode” production, human geography and other non-technical factors. (4) Process economic evaluation under the conditions of government financial subsidies. China's shale gas project FIRR is about 8.0%–9.0%. Considering the global shale gas resources, consumer demand and other factors, it global shale gas production is expected to reach 1.1 × 1012m3 by 2040. Keywords: Shale gas, Black shale, Shale gas revolution, Nano pore, Sweet spot area, Sweet spot section, Artificial gas reservoir

With the rapid progress of hardware and software, a wireless sensor network has been widely used in many applications in various fields. However, most discussions for the WSN node deployment mainly concentrated on the two-dimensional plane. In such a case, some large scale applications, such as information detection in deep space or deep sea, will require a good three dimensional (3D) sensor deployment scenario and also attract most scientists’ interests. Excellent deployment algorithms enable sensors to be quickly deployed in designated areas with the help of unmanned aerial vehicles (UAVs). In this paper, for the first time, we present a three dimensional network deployment algorithm inspired by physical dusty plasma crystallization theory in large-scale WSN applications. Four kinds of performance evaluation methods in 3D space, such as the moving distance, the spatial distribution diversion, system coverage rate, and the system utilization are introduced and have been carefully tested.Furthermore, in order to improve the performance of the final deployment, we integrated the system coverage rate and the system utilization to analyze the parameter effects of the Debye length and the node sensing radius. This criterion attempts to find the optimal sensing radius with a fixed Debye length to maximize the sensing range of the sensor network while reducing the system redundancy. The results suggest that our 3D algorithm can quickly complete an overall 3D network deployment and then dynamically adjust parameters to achieve a better distribution. In practical applications, engineers may choose appropriate parameters based on the sensor’s hardware capabilities to achieve a better 3D sensor network deployment. It may be significantly used in some large-scale 3D WSN applications in the near future.

The unconventional yeast Yarrowia lipolytica is extensively applied in bioproduction fields owing to its excellent metabolite and protein production ability. Nonetheless, utilization of this promising host is still restricted by the limited availability of precise and effective gene integration tools. In this study, a novel and efficient genetic tool was developed for targeted, repeated, and markerless gene integration based on Cre/lox site-specific recombination system. The developed tool required only a single selection marker and could completely excise the unnecessary sequences. A total of three plasmids were created and seven rounds of marker-free gene integration were examined in Y. lipolytica. All the integration efficiencies remained above 90%, and analysis of the protein production and growth characteristics of the engineered strains confirmed that genome modification via the novel genetic tool was feasible. Further work also confirmed that the genetic tool was effective for the integration of other genes, loci, and strains. Thus, this study significantly promotes the application of the Cre/lox system and presents a powerful tool for genome engineering in Y. lipolytica.

Abstract MCM7, a subunit of mini-chromosome maintenance proteins (MCM) complex, plays an important role in initiating DNA replication during the G1 phase and extending DNA strands during the S phase. Here, we demonstrated that MCM7 is not only sustained but maintains association with chromatin during M phase. Remarkably, MCM7 siRNA can accelerate mitotic exit. MCM7 depletion leads to CDK1 inactivation and promotes subsequent cohesin/RAD21 cleavage, which eventually leads to sister chromatin segregation. Moreover, MCM7 is co-localized with tubulin in the mitotic cells and MCM7 depletion results in aberrant mitosis. Our results indicate that MCM7 may exert certain functions on spindle formation to prevent cytokinesis during early mitosis by regulating CDK1 activity.

A prerequisite to effective shale gas development is a complicated fracture network generated by extensive and massive fracturing, which is called SRV (stimulated reservoir volume) section. Accurate description of gas flow behaviors in such section is fundamental for productivity evaluation and production performance prediction of shale gas wells. The SRV section is composed of bedrocks with varying sizes and fracture networks, which exhibit different flow behaviors – gas diffusion in bedrocks and gas seepage in fractures. According to the porosity and permeability and the adsorption, diffusion and seepage features of bedrocks and fractures in a shale gas reservoir, the material balance equations were built for bedrocks and fractures respectively and the continuity equations of gas diffusion and seepage in the SRV section were derived. For easy calculation, the post-frac bedrock cube was simplified to be a sphere in line with the principle of volume consistency. Under the assumption of quasi-steady flow behavior at the cross section of the sphere, the gas channeling equation was derived based on the Fick's laws of diffusion and the density function of gas in bedrocks and fractures. The continuity equation was coupled with the channeling equation to effectively characterize the complicated gas flow behavior in the SRV section. The study results show that the gas diffusivity in bedrocks and the volume of bedrocks formed by volume fracturing (or the scale of fracturing) jointly determines the productivity and stable production period of a shale gas well. As per the actual calculation for the well field A in the Changning–Weiyuan Block in the Sichuan Basin, the matrix has low gas diffusivity – about 10−5 cm2/s and a large volume with an equivalent sphere radius of 6.2 m, hindering the gas channeling from bedrocks to fractures and thereby reducing the productivity of the shale gas well. It is concluded that larger scale of volume fracturing and higher fracture density in the SRV section are important guarantees for efficient development of shale gas reservoirs.