Search

The complex network of fractures formed by randomly distributed natural fractures in hot-dry rocks (HDRs) complicates the heat transfer regularity of injected fluid. On the basis of the fracture network, exploring the characteristics of the fluid flow and heat transfer as influenced by different parameters helps enable efficient resource extraction and effectively promotes the construction of diversified energy utilization structures. Accordingly, accounting for the effect of the thermal shock on the evolution of the permeability of the rock matrix, a thermo-hydro-mechanical (THM) coupling model is developed to analyze the influences of fracture network characteristics on the heat extraction performance of HDRs. In addition, a large-scale injection and production physical simulation experiment is performed using a newly developed, in-house, large-scale true triaxial experimental system. The corresponding numerical model is established and validated. The good agreement between the numerical and experimental results verifies the reliability and accuracy of the proposed THM model. Subsequently, a two-dimensional model is established under complex fracture network conditions, taking, as a research object, the natural fracture characteristics of HDR in the Qinghai Gonghe Basin in combination with the regional geological information. The effects of different parameters, including the production well location, rock matrix permeability, injection rate, initial fracture width, and number of fractures, on the production temperature and heat extraction performance are systematically analyzed. The results indicate that an increase in the number of fractures, the distance between the injection well and the production well, or the width of the initial fractures leads to an improved heat extraction performance. The number of fractures increased from 11 horizontal fractures and 22 high-angle fractures to 35 horizontal fractures and 70 high-angle fractures, with a 20% increase in heat extraction rate. While the influence of the rock matrix permeability is not highly significant, it cannot be ignored. It is crucial to select an injection rate that is neither too low nor too high, taking into consideration economic factors.

ObjectiveTo evaluate the performance of a clinical-radiomics model based on contrast-enhanced computed tomography (CE-CT) in assessing human epidermal growth factor receptor 2 (HER2) status in urothelial bladder carcinoma (UBC).MethodsFrom January 2022 to December 2023, 124 patients with UBC were classified into the training (n=100) and test (n=24) sets. CE-CT scans were performed on the patients. Univariate and multivariate analyses were conducted to identify independent predictors of HER2 status in patients with UBC. We employed eight machine learning algorithms to establish radiomic models. A clinical-radiomics model was developed by integrating radiomic signatures and clinical features. Receiver operating characteristic curves and decision curve analysis (DCA) were generated to evaluate and validate the predictive capabilities of the models.ResultsAmong the eight classifiers, the random forest radiomics model based on CE-CT demonstrated the highest efficacy in predicting HER2 status, with area under the curve (AUC) values of 0.880 (95% CI: 0.813–0.946) and 0.814 (95% CI: 0.642–0.986) in the training and test sets, respectively. In the training set, the clinical-radiomics model achieved an AUC of 0.935, an accuracy of 0.870, a sensitivity of 0.881, and a specificity of 0.854. In the test set, the clinical-radiomics model achieved an AUC of 0.857, an accuracy of 0.760, a sensitivity of 0.643, and a specificity of 0.900. DCA analysis indicated that the clinical-radiomics model provided good clinical benefit.ConclusionThe radiomics nomogram demonstrates good diagnostic performance in predicting HER2 expression in patients with UBC.

Abstract Growing evidence has demonstrated that cold and humid environmental stress triggers gastrointestinal (GI) disorders. In this study, we explored the effects of intestinal microbiota homeostasis on the intestinal mucus barrier and GI disorders by cold and humid environmental stress. Moreover, the inner link between the intestinal mucosal microbiota and metabolites in mice with cold and humid environmental stress was interpreted by integrative analysis of PacBio HiFi sequencing microbial genomics and targeted metabolomics. In the current study, we found (1) after the cold and wet cold and humid environmental stress intervened in the intestinal microbiota disorder and homeostasis mice respectively, the bacterial culturing and fluorescein diacetate (FDA) microbial activity detection of intestinal microbiota including feces, intestinal contents, and intestinal mucosa suggested that the cold and humid environmental stress decreased the colony of culturable bacteria and microbial activity, in which intestinal microbiota disorder aggravated the injury of the intestinal mucus barrier and the GI symptoms related to cold and humid environmental stress; (2) the serum amino acid transferases such as glutamate pyruvic transa (GPT), and glutamic oxaloacetic transaminase (GOT) in cold and humid environmental stressed mice increased significantly, indicating that the intestinal microbiota adapted to cold and humid environmental stress by regulating the host's amino acid metabolism; (3) the integrative analysis of multi-omics illustrated a prediction model based on the microbiota Lactobacillus reuteri abundance and host amino acid level that can predict intestinal mucoprotein Muc2 with an adjusted R2 of 75.0%. In conclusion, the cold and humid environmental stress regulates the neurotransmitter amino acids metabolic function both in intestinal mucosal microbiota and host serum by adjusting the composition of the dominant bacterial population Lactobacillus reuteri, which contributes to the intestinal mucus barrier injury and GI disorders caused by cold and humid environmental stress.

To study material erosion and deposition during different wall conditioning processes in the Experimental Advanced Superconducting Tokamak (EAST), two newly developed quartz crystal microbalances (QMBs) at the mid-plane of port C (C-QMB) and port J (J-QMB) with the same radial radius were used for in-situ and real-time measurements during the 2021 autumn experimental campaign. It was found that the material deposition was mainly influenced by the location of the antenna and the power of the ion cyclotron range of frequency (ICRF), rather than the location of the gas inlet, during the wall cleaning with helium plasma and siliconization assisted with ICRF plasma. The higher energy and density of plasma could result in higher deposition rates near the antenna. While, during lithium (Li) coating, the material deposition was greatly influenced by the location of the Li oven due to the deposition of unionized Li atoms. The ICRF power influenced the material deposition behavior far away from the Li ovens. Besides, a stronger effect on impurity suppression was observed with a more uniform deposition trend of Li coating. This necessitates further study on the influence of factors such as the location of the Li oven and ICRF antenna, the temperature of ovens, and ICRF power on the homogeneity of wall conditioning.

Melatonin (Mel) is an endogenous active molecule whose metabolism progress significantly influences its bioactivity. However, the detailed metabolic pathway of Mel in the pathological state has not yet been fully illustrated. In this study, 16 metabolites of Mel in cancer cells and human liver microsomes were identified, of which seven novel metabolites were newly discovered. Among them, 2-hydroxymelatonin (2-O-Mel), as the major metabolite in cancer cells, was revealed for the first time, which was different from the metabolite found in the human liver. Furthermore, CYP1A1/1A2- and reactive oxygen species (ROS)-mediated 2-hydroxylation reactions of Mel were verified to be the two metabolic pathways in the liver and cancer cells, respectively. ROS-dependent formation of 2-O-Mel was the major pathway in cancer cells. Furthermore, the underlying catalytic mechanism of Mel to 2-O-Mel in the presence of ROS was fully elucidated using computational chemistry analysis. Therefore, the generation of 2-O-Mel from Mel could serve as another index for the endogenous reactive oxygen level. Finally, based on the ROS-dependent production of 2-O-Mel, Mel was successfully used for detecting the oxygen-carrying capacity of hemoglobin in human blood. Our investigation further enriched the metabolic pathway of Mel, especially for the ROS-dependent formation of 2-O-Mel that serves as a diagnostic and therapeutic target for the rational use of Mel in clinics.

The maintenance, inspection, and refurbishment of substation equipment are crucial for ensuring the stability of the power grid’s operation and the reliability of power supply to users. However, currently, there is a lack of methods for rapidly and effectively planning load transfer solutions during substation equipment maintenance periods. To address this, this study is founded on the principles of transmission network planning theory, and an analysis of the similarities and disparities between the planning methods for load transfer solutions during substation equipment maintenance and traditional approaches to transmission network planning is conducted. Furthermore, this paper integrates practical constraints related to maintenance engineering and power grid load flow balance constraints. With the primary optimization objectives of minimizing investment and operational costs during system maintenance while maximizing power grid reliability, a load transfer planning model for equipment maintenance in the substation has been developed. Simultaneously, in conjunction with linear programming theory, the nonlinear constraint terms of the model have been equivalently simplified to enhance the computational performance of the model. Simulation analysis is conducted on case studies constructed based on the IEE-RBTS6 and IEEE-RTS79 systems to validate the effectiveness of the proposed model in solving the optimal maintenance planning problem.

At present, the application prospect of superhydrophobic materials in oil-water separation, an-tibacterial and other aspects have attracted more and more attention. However, preparing a simple and low-cost superhydrophobic material remains a challenge. Using acetone as solvent, candle soot, silver/silica nanoparticles and polydimethylsiloxane were uniformly mixed to form a mixed solution, and the superhydrophobic sponge was successfully prepared by spraying method. The results show that the superhydrophobic sponge has high water contact Angle (162°) and excellent oil-water separation efficiency, which can realize effective treatment of polymerized wastewater. In addition, the superhydrophobic sponge showed better antibacterial properties on the surface of Escherichia coli and Staphylococcus aureus. In this work, a simple way to prepare superhydro-phobic oil-water separation material is proposed. The preparation process is green, the material is easy to obtain, and it is expected to be widely used in practical production.

As the burial depth of shale exploitation increases, it is challenge to form fracture networks through hydraulic fracturing technology. When cryogenic fluid contacts with hot rock, heat exchange process occurs and temperature gradient is generated at the rock surface, resulting in thermal stress. Once the thermal stress exceeds the tensile strength, the fractures are generated. To study the initiation and propagation of fractures induced by thermal shock, a thermal-mechanical (TM) coupled two-dimensional model is developed in the paper. To simulate the heat exchange process, the heat convective boundary is applied in the surface between the fluid and the rock. In addition, the initiation and propagation of fractures are described by the cohesive zone model. The accuracy and reliability of the numerical model is validated by an existing analytical solution. Under the thermal shock, the temperature at the contact surface drops quickly. The stress distribution is determined by the temperature variation. The variations of temperature and stress are greatly affected by the heat exchange coefficient. With the fractures embedded in the model, the initiation and propagation of fractures are analysed. The multi-fracture propagation induced by thermal shock exhibits competition effect. With the propagation of fractures, the stress distribution in the rock changes. The heat exchange coefficient has a significant effect on fracture initiation and propagation, presenting more fractures generation in the larger coefficient.

Toxoplasma gondii is the causative agent of toxoplasmosis, a zoonotic disease that poses a threat to human health and a considerable loss to livestock farming. At present, clinical therapeutic drugs mainly target T. gondii tachyzoites and fail to eradicate bradyzoites. Developing a safe and effective vaccine against toxoplasmosis is urgent and important. Breast cancer has become a major public health problem and the therapeutic method needs to be further explored. Many similarities exist between the immune responses caused by T. gondii infection and the immunotherapy for cancers. T. gondii dense granule organelles secrete immunogenic dense granule proteins (GRAs). GRA5 is localized to the parasitophorous vacuole membrane in the tachyzoite stage and the cyst wall in the bradyzoite stage. We found that T. gondii ME49 gra5 knockout strain (ME49Δgra5) was avirulent and failed to form cysts but stimulated antibodies, inflammatory cytokines, and leukocytes infiltration in mice. We next investigated the protective efficacy of ME49Δgra5 vaccination against T. gondii infection and tumor development. All the immunized mice survived the challenge infection of either wild-type RH, ME49, VEG tachyzoites, or ME49 cysts. Moreover, ME49Δgra5 tachyzoite inoculation in situ attenuated the growth of murine breast tumor (4T1) in mice and prevented 4T1’s lung metastasis. ME49Δgra5 inoculation upregulated the levels of Th1 cytokines and tumor-infiltrating T cells in the tumor microenvironment and triggered anti-tumor responses by increasing the number of natural killer, B, and T cells, macrophages, and dendritic cells in the spleen. Collectively, these results suggested that ME49Δgra5 was a potent live attenuated vaccine against T. gondii infection and breast cancer.

By means of X-ray diffraction analysis, scanning electron probe microanalysis and optical microscopy, the chemical composition and mineral intercalation and particle size composition of potassium feldspar in Jilin were studied. The results show that main minerals in the ore is potassium feldspar, albite and quartz, and the iron elements are mainly distributed in hematite, limonite and magnetite. Potassium feldspar is present in the form of needle-shaped fine grain and some iron ore is embedded in the microcrystalline base of potassium feldspar and the edge of hole or immersed in gangue mineral, so the ore belongs to a more difficult ore. In the ore that particle size less than 0.0385 mm, the Fe2O3 content reaches 2.36%. All that means the sample needs to be desliming, magnetic separation, flotation and pickling in the follow-up treatment to make the product meet the high-end potassium feldspar market requirements.

Algorithms for noise removal are either complex or ineffective, and the optimal control with inequality constrains makes the algorithm even more complex. Now the condition is changed completely, and the tropical algebra is an extremely simple tool for this purpose. The tropical algebra-based filter has obvious advantages over traditional ones, and an inequality constrain can be converted to a tropical polynomial, making the tropical algebra much attractive in engineering applications. In this paper, idempotents on multiplicative semigroups of tropical matrices are studied. First, the concepts of tropical algebra and the semigroup of tropical matrices under multiplication are introduced. Second, the structure of idempotents on the semigroup of 3 × 3 tropical matrices under multiplication is given. Finally, as examples, the tropical addition is used as a filter for noise removal, and a simple optimization is given where the constraint is given by the tropical algebra. The paper has opened the path for a new way to noise removal and optimization.

Circulating tumor cells (CTCs), as important liquid biopsy target, can provide valuable information for cancer progress monitoring and individualized treatment. However, current isolation platforms incapable of balancing capture efficiency, specificity, cell viability, and gentle release have restricted the clinical applications of CTCs. Herein, inspired by the structure and functional merits of natural membrane interfaces, we established an antibody-engineered red blood cell (RBC-Ab) affinity interface on microfluidic chip for high-performance isolation and release of CTCs. The lateral fluidity, pliability, and anti-adhesion property of the RBC microfluidic interface enabled efficient CTCs capture (96.5%), high CTCs viability (96.1%), and high CTCs purity (average 4.2-log depletion of leukocytes). More importantly, selective lysis of RBCs by simply changing the salt concentration was utilized to destroy the affinity interface for efficient and gentle release of CTCs without nucleic acid contamination. Using this chip, CTCs were successfully detected in colon cancer samples with 90% sensitivity and 100% specificity (20 patients and 10 healthy individuals). After the release process, KRAS gene mutations of CTCs were identified from all the 5 cancer samples, which was consistent with the results of tissue biopsy. We expect this RBC interface strategy will inspire further biomimetic interface construction for rare cell analysis.

In the Internet era, there is a mismatch between the skill demands of the IT industry in China and the employment prospects of computer science graduates. The COVID-19 pandemic has particularly highlighted co-existing challenges for industry recruitment and student employment. Many education institutions see IT skills training as a way to solve this conflict. The present paper employs a mixed methods approach to explore factors regarding computer science students' employability. The study used a questionnaire informed by an indepth literature review, full scale development theory and the theory of competency-based education. Reliability analysis and factor analysis methods were used to assess component reliability and structural validity. A total of 323 valid questionnaires were collected and subjected to mean and variance analyses to explore significant differences, including in terms of gender, in student employability. The results show that: (1) employability is divided into nine factors; (2) IT skills training can improve employability; (3) the employability level of computer science students who participate in IT skills training is high; (4) there are significant gender differences in professional ethics, scientific spirit and job-seeking skills, but no significant gender differences in humanistic qualities, computer cognition and operation skills, software design and development skills, system use and innovation skills, sustainable development capacity and teamwork skills. The identification of student employability factors can help education institutions to improve their training and can be used as a standard for students' self-evaluation and selfimprovement. The paper also provides suggestions for education institutions about how to set up IT skills training programmes to enhance students' future employment prospects in the IT industry.

In the wake of the COVID-19 pandemic in 2019, China’s education leaders began to focus on and promote blended learning. The process is still in its infancy in Chinese colleges and universities, and its development remains a problem to be solved. By combining technology acceptance and student participation, this article proposes an analysis model for assessing the factors influencing blended learning. A questionnaire was designed and distributed, and 796 valid responses were collected. The mean and variance were used to examine the status of students’ technology acceptance and satisfaction with blended learning. The t-test method was employed to analyze the gender differences between students in regard to the topic. The results show that: (1) students majoring in computer science view the factors as having a high level of influence in blended learning. (2) There are major variances regarding the perception of service quality between male and female computer science major students. There is no significant difference between them in terms of perceived usefulness, perceived ease of use, or computer self-efficacy. (3) There are considerable disparities in the skill involvement and participation of computer science major college students. The results show that the technology acceptance and participation of students determine the effect of blended learning. Based on these findings, this article provides theoretical and practical suggestions for the implementation of blended learning to improve its effect.