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SummarySuccessful fracturing operations heavily rely on the performance of fracturing fluids (FFs), which mainly include high sand-carrying capacity (SCC) and significant drag reduction (DR). Herein, a functional copolymer, SRP-6, was synthesized by introducing a zwitterionic surfactant, 4-((3-((3-(docos-10-enamido)propyl)dimethylammonio)-2-hydroxypropyl)amino)benzenesulfonate (SVBS), during polymerization, and its structure was characterized by Fourier transform infrared and 1H nuclear magnetic resonance (NMR). SRP-6 shows superior solubility, hydrodynamic volume, and microstructure in salinity water, thanks to the hydrophilicity of multiple functional groups in the copolymer structure, and the SVBS-induced pseudointerpenetrated network as well as the uniform distribution of multiple functional monomers. Furthermore, the SVBS, as a physical crosslinker, imparts the SRP-6/SVBS solution with outstanding rheological performance, SCC, and DR. In addition, the contribution of elasticity and viscosity to SCC was calculated. These results collectively suggest that the SRP-6/SVBS solution could be potentially used as a high-performance FF for the development of tight reservoirs.

Tandem spinal stenosis refers to simultaneous spinal canal stenosis of noncontiguous regions. There is no consensus in the surgical strategies for patients with symptomatic tandem spinal stenosis because of the confusing clinical manifestations. This meta-analysis aimed to compare the outcomes of one-stage and two-stage decompression of all stenotic regions (cervical and lumbar/thoracic segments) in patients with TSS.A systematic review was conducted, and a comprehensive literature search with the Japanese Orthopedic Association score, was carried out using MEDLINE, Web of Science and PubMed databases from inception to September 13, 2022. Observational studies reporting the outcomes after one-stage or two-stage decompression of all symptomatic regions were included. Possible heterogeneity among studies was assessed by the Higgins' IThirteen retrospective observational studies were included in this meta-analysis. Meta-analysis showed that there was no significant difference in the JOA improvement in patients with TSS involving either the cervical-thoracic or cervical-lumbar segments. Regarding the surgical parameters and complications, one-stage decompression showed comparable operation time, blood loss and major complications to two-stage decompression in patients with cl-TSS. In patients with ct-TSS, one-stage decompression had significant advantages compared with two-stage decompression in operation time, blood loss and major complications.For patients with cl-TSS, two-stage decompression exhibited slight advantages in clinical outcome without exposing patients to unnecessary surgical risks. For Patients with ct-TSS, one-stage decompression showed comparable clinical outcome whereas with better operative parameters and lower complication rate than simultaneous decompression.

A cross-sectional study.To quantify the severity of neurogenic intermittent claudication (NIC) for patients with lumbar spinal stenosis (LSS) based on the center of pressure trajectory.NIC is one of the typical symptoms of LSS. So far, the severity level of NIC is mainly evaluated by the subjective description of patients, which might be biased by patients' background differences and thus lead to an ineffective diagnosis or inappropriate treatment for LSS. Therefore, it remains necessary to develop a reliable clinical technique for quantitative evaluation of NIC to achieve more effective therapy for LSS.In the present study, the Footscan pressure system was used to detect the center of pressure trajectory. The real-time walking distance (rtWD) and the corresponding displacement of the medial-lateral center of pressure (ML-COP) were calculated based on the trajectory. The differences of ML-COP between LSS and control groups were analyzed using a one-way repeated measures analysis of variance. Regression and Pearson correlation analysis were used to investigate the correlation between rtWD and ML-COP, as well as the relation between the Oxford Claudication Score (OCS) and clinical evaluation indicators.The present study included 31 LSS patients and 31 healthy controls. There were no significant differences in demographic data between the two groups ( P0.05). The results indicated that ML-COP would increase with the number of laps in the LSS group while not in the control group. Also, a linear relationship was identified between the ML-COP and rtWD for LSS patients ( R20.80, P0.05). Since the incremental rate of ML-COP for LSS patients was reflected by the regression coefficients of the linear regression analysis, thus the regression coefficients were defined as the claudication correlation coefficients (CCCs). In addition, it was indicated by the statistical analysis that there was a strong positive correlation between OCS and CCC ( r =0.96; P0.001) and a medium negative correlation with final walking distance ( r =-0.67; P0.001). It was also noticed that there was no significant correlation between the average ML-COP and OCS ( r =-0.03; P =0.864).The ML-COP of LSS patients would increase with the patients' walking distance. This incremental rate, characterized by the CCC, would be used as an effective indicator to quantify the severity level of the NIC for potentially more accurate and reliable diagnosis, evaluation, and treatment of LSS.3.

Significant research focus has recently been directed toward energy-saving and emission-reduction practices, as well as the unique benefits of an integrated working fluid in the oilfield industry. Surfactants cannot be widely used in engineering practice due to cost constraints. At the same time, there is no proper solution to the flowback liquid problem. SY-JS, a multifunctional surfactant, was developed to broaden the application of surfactants in the oilfield industry. It still meets the field operation requirements of a good fracturing fluid thickener with a shear rate of 170 s-1 at 140�C and salinity (NaCl or KCl) of 12-13%. When the fracturing fluid has finished its job and returns to the ground, the molecular structure of the surfactant in the flowback fluid was found to be complete after laboratory evaluation of the fracturing and oil displacement integrated working fluid systems. Surfactants with an intact molecular structure should retain their distinct lipophilic and hydrophilic properties. When groundwater and produced water are compounded and re-injected into the reservoir for oil displacement, 0.2 percent anionic surfactant B1-12 is used to balance the charge and reduce interfacial tension. The rock`s contact angle can be reduced by 56.95 percent, and the recovery rate can be increased by 6%. Based on these findings, the surfactant`s dynamic self-healing mechanism was proposed. Furthermore, the capillary force, interfacial tension, and wettability were combined to propose wettability determines capillary force direction and interfacial tension determines capillary force magnitude. Furthermore, it provides favorable evidence that interfacial tension does not always reach ultralow levels during reservoir exploitation.

Existing detection methods commonly use a parameterized bounding box (BBox) to model and detect (horizontal) objects and an additional rotation angle parameter is used for rotated objects. We argue that such a mechanism has fundamental limitations in building an effective regression loss for rotation detection, especially for high-precision detection with high IoU (e.g. 0.75). Instead, we propose to model the rotated objects as Gaussian distributions. A direct advantage is that our new regression loss regarding the distance between two Gaussians e.g. Kullback-Leibler Divergence (KLD), can well align the actual detection performance metric, which is not well addressed in existing methods. Moreover, the two bottlenecks i.e. boundary discontinuity and square-like problem also disappear. We also propose an efficient Gaussian metric-based label assignment strategy to further boost the performance. Interestingly, by analyzing the BBox parameters' gradients under our Gaussian-based KLD loss, we show that these parameters are dynamically updated with interpretable physical meaning, which help explain the effectiveness of our approach, especially for high-precision detection. We extend our approach from 2-D to 3-D with a tailored algorithm design to handle the heading estimation, and experimental results on twelve public datasets (2-D/3-D, aerial/text/face images) with various base detectors show its superiority., Comment: 19 pages, 11 figures, 16 tables, accepted by TPAMI 2022. Journal extension for GWD (ICML'21) and KLD (NeurIPS'21). arXiv admin note: text overlap with arXiv:2101.11952

Grazing exclusion changes soil physical-chemical characteristics, rapidly affects microbial community composition and function, and alters biogeochemical processes, e.g., carbon (C) cycle, over time. However, the temporal dynamics of CO2 emission and CH4 uptake during grassland restoration chronosequences remain poorly understood. We investigated soil CO2 emission and CH4 uptake, the genes related to CO2 and CH4 production and reduction (cbbL, cbbM, chiA, and pmoA), and associated microbial communities under different durations of grazing exclusion (0, 7, 16, 25, and 38 years) to reveal the mechanisms and potential of soil CO2 emission and CH4 uptake in a semi-arid steppe. The results showed that a proper exclusion period could significantly improve soil physical-chemical conditions, vegetation community, and soil C-cycling. The abundance of C-cycling functional genes (cbbL, cbbM, chiA and pmoA), CH4 uptake and CO2 emission rates showed a single-peak pattern with increasing duration of grazing exclusion, peaking at 16 years and then decreasing in the period between 25 and 38 years, indicating that the effect of exclusion weakened when the exclusion period was too long. The changes in C-cycling functional genes and microbial communities are primarily influenced by aboveground net primary productivity (ANPP), and are associated with CO2, CH4, soil water content (SWC), and soil organic carbon (SOC). Structural equation modeling showed that increases in SOC content and pmoA abundance caused by an increase in ANPP accelerated CO2 emission and CH4 uptake rates, respectively. Our results provide valuable insights into the critical role of grazing exclusion in promoting grassland restoration and carbon sequestration, and have potential implications for sustainable land management practices.

Lateral changes in velocity about faults can give rise to fault shadow (FS) zones on time-migrated data volumes, which can result in structural interpretation artifacts in the fault trap reservoir. To address this issue, we have adopted a new reconstruction method of FS distortion structures based on a deep learning fully connected network (FCN). We use the 3D stratigraphic dip attributes to quantitatively delineate the extent of the FS zone. Then, we train a model to construct a nonlinear trend surface based on the structures of the stratigraphic reflectors that fall outside of the shadow zone. Finally, we use this nonlinear trend surface to compensate for the distorted structure within the FS zone. We calibrate our method using synthetic data and find that the method can accurately recover structural data within the FS distortion zone. We then test the effectiveness of our workflow by applying it to recover real FS distortion structures in the Pearl River Mouth Basin of the South China Sea. The results confirm that our method significantly reduces drilling depth errors in the FS zone. Compared to the traditional polynomial fitting method, the multilayer, multiparameter, and flexible nonlinear activation function of FCN is more capable of reconstructing nonlinear geologic structures in the FS zone. We find the FCN-based geologic reconstruction method to be efficient and effective for exploring potential structures in the FS zone and thereby in avoiding the risks of structural failure.

The poor targeting capability of systemically administered drugs is a major hurdle in designing effective therapies with minimal off-target side effects. Here, as a proof of concept, we propose a genetic engineering strategy to embed a prostate-specific membrane antigen (PSMA)-targeting antibody fragment (gy-1) in the macrophage membrane, which is then coated onto core-shell Fe3O4@Au nanoparticles to produce a biomimetic nanoplatform, Magic. The results indicate that Magic exhibits not only high specificity and affinity towards prostate tumor cells in vitro and in vivo, but also effective immunomodulatory capability. Upon further encapsulation with the anti-tumor drug DM1, Magic shows superior synergistic effects in highly targeted chemo-photothermal therapy and potent immunotherapy, eliciting significant therapeutic efficacy against tumor growth, micro-metastasis and concomitant damage without overt toxicity. These findings reveal that Magic may provide a promising platform for enhancing cancer treatment by overcoming undesired drug delivery barriers and the tumor immune microenvironment.

The investigation into the effects of acidizing treatment on the mechanical property of hot dry rocks (HDR) is beneficial for our understanding of the fracturing and stimulation mechanisms in HDR reservoirs. In this article, Brazilian disk tests were first carried out for hollow hot dry rocks with different internal diameters after acidizing treatments. The influences of acidizing treatments on the physical properties, tensile strength, and failure patterns of hot dry rock specimens were presented. Besides, the effects of the diameter of the internal hole on the peak load and failure patterns of the hot dry rock specimens were also investigated. The peak load decreases with the increase in the internal diameter. The results indicated that the acidizing treatments can dissolute the minerals, decrease rock mass, and tensile strength. The investigation of failure patterns demonstrated that the acidizing treatment is beneficial for the fracturing of hot dry rocks. The present study can provide some basic and theoretical data for the development of geothermal reservoir.

Designed and synthesized two corrosion inhibitors that can resist corrosion of low-carbon steel in high-salinity corrosive media. When these compounds are used as corrosion inhibitors in high salinity corrosive media, the laboratory evaluation results clearly showed that the two corrosion inhibitors had an excellent corrosion resistance. The synthetic corrosion inhibitors have an symmetrical structure which not only has a symmetrical appearance but also has the practical significance of forming an entire surface covering layer, which avoids the general corrosion and pitting corrosion.

Exploring ways to efficiently and inexpensively exploit and transport high-viscosity and high-pour-point crude oil is very important, and use of silica nanoparticles (nano-SiO2) to reduce the pour ...

Deep clustering refers to joint representation learning and clustering using deep neural networks. Existing methods can be mainly categorized into two types: discriminative and generative methods. The former learns representations for clustering with discriminative mechanisms directly, and the latter estimate the latent distribution of each cluster for generating data points and then infers cluster assignments. Although generative methods have the advantage of estimating the latent distributions of clusters, their performances still significantly fall behind discriminative methods. In this work, we argue that this performance gap might be partly due to the overlap of data distribution of different clusters. In fact, there is little guarantee of generative methods to separate the distributions of different clusters in the data space. To tackle these problems, we theoretically prove that mutual information maximization promotes the separation of different clusters in the data space, which provides a theoretical justification for deep generative clustering with mutual information maximization. Our theoretical analysis directly leads to a model which integrates a hierarchical generative adversarial network and mutual information maximization. Moreover, we further propose three techniques and empirically show their effects to stabilize and enhance the model. The proposed approach notably outperforms other generative models for deep clustering on public benchmarks.

Hydrophobic associated polymer is widely used as fracturing fluids, but its cost is often higher than natural polymers. In order to reduce the cost, quaternary polymer AM/AA/NVP/MAO-12DAM (AANM) was successfully synthesized. The incorporation of N-vinyl-2-pyrrolidone (NVP) improves the temperature resistance of the polymer solution. Rheological and viscoelasticity test results showed that fluids with a lower dosage of AANM in the absence of any crosslinker had better performances than Guar gum (GG) with a crosslinker. Therefore, AANM is expected to be a more economical fracturing fluid thickener than GG.

In this study, a gemini zwitterionic viscoelastic surfactant with a sulfonic group, named VES-S, was synthesized. The surface activity properties of VES-S were found to show an ultra-low sensitivity to the salt concentration compared to those of cationic gemini surfactants, meaning that the packing parameter of VES-S varies little with increasing salinity. Through laboratory measurements, it was found that the addition of salt can enhance the viscoelasticity of the VES-S solution by tightening the net-work structure even at a high NaCl concentration (8 wt%), which indicated that VES-S was a viscoelastic surfactant with high salt tolerance. A series of laboratory evaluations showed that the clean fracturing fluids prepared by VES-S and simulated seawaters fulfilled the requirements for hydraulic fracturing operations, which proved that VES-S was an excellent and reliable viscoelastic surfactant with a high salt tolerance that can be used to prepare seawater-based clean fracturing fluids.

The content of insoluble substance in guar gum solution is high and its temperature resistance is poor. A novel anionic guar gum (GG) derivative was developed and grafted by modification with maleic anhydride. Compared with guar gum, the insoluble content of MAG solution decreased from 13 to 5%, the decomposition temperature of MAG increased from 285 to 308, and the viscoelasticity of MAG gel has been enhanced, especially elasticity. The rheological tests show that the corresponding fracturing fluid belongs to a non-Newtonian pseudoplastic one and the viscosity could maintain 50 mPa∙s for 2 h under conditions of 150 °C and 170 s−1, which can be applied in a high-temperature well. It is noteworthy that the synthetic protocol of maleate esters guar gum (MAG) is easily available, low cost, and practical. It is conducive to the industrial application of MAG. The work showed a great significance to the modification of GG with acid anhydride for fracturing fluid.