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In response to the inability of the flexible DC transmission system connected to the AC grid under conventional control strategies to provide inertia to the system as well as to participate in frequency regulation, a virtual synchronous generator (VSG) control strategy is proposed for a voltage source converter (VSC)-based multi-terminal high-voltage direct current (VSC-MTDC) interconnection system. First, the virtual controller module is designed by coupling AC frequency and active power through virtual inertia control, so that the VSC-MTDC system can provide inertia response for AC grid frequency. Second, by introducing the power margin of the converter station into the droop coefficient, the unbalanced power on the DC side is reasonably allocated to reduce the overshoot of the DC voltage in the regulation process. Finally, the power regulation capability of the normal AC system is used to provide power support to the fault end system, reducing frequency deviations and enabling inter-regional resource complementation. The simulation model of the three-terminal flexible DC grid is built in PSCAD/EMTDC, and the effectiveness of the proposed control strategy is verified by comparing the conventional control strategy and the additional frequency control strategy. [ABSTRACT FROM AUTHOR]

As an important free energy source, the membrane voltage (Vm) regulates many essential physiological processes in bacteria. However, in comparison with eukaryotic cells, knowledge of bacterial electrophysiology is very limited. Here, we developed a set of novel genetically encoded bacterial Vm sensors which allow single-cell recording of bacterial Vm dynamics in live cells with high temporal resolution. Using these new sensors, we reveal the electrically "excitable" and "resting" states of bacterial cells dependent on their metabolic status. In the electrically excitable state, frequent hyperpolarization spikes in bacterial Vm are observed, which are regulated by Na+/K+ ratio of the medium and facilitate increased antibiotic tolerance. In the electrically resting state, bacterial Vm displays significant cell-to-cell heterogeneity and is linked to the cell fate after antibiotic treatment. Our findings demonstrate the potential of our newly developed voltage sensors to reveal the underpinning connections between bacterial Vm and antibiotic tolerance. [ABSTRACT FROM AUTHOR]

Improving the detection accuracy of hyperbola in B-scan images has been a considerable challenge for ground penetrating radar (GPR) to detect tree roots. In this paper, a method for data enhancement and target detection, both based on deep learning was proposed to identify hyperbolas in GPR B-scan images. First, the authors used a cyclic consistent adversarial network (CycleGAN) to augment the original data. In this procedure, the hyperbolic features of the images were preserved and created a wider variety of training samples. Then, the authors could apply the enhanced dataset to the YOLOv5 detection model to evaluate the effectiveness of their method. Meanwhile, the detection effects of Yolov3, Yolov5, Faster R-CNN, and CenterNet detection models on the enhanced dataset were compared. The results showed that applying the enhanced dataset to the Yolov5 detection model exhibited better detection accuracy compared to other combinations of datasets and detection models. The authors demonstrate that the proposed method increases data diversity and the number of samples, improving the precision and recall of hyperbolic curves. These results provide a new method for tree root localization with important effects. [ABSTRACT FROM AUTHOR]

In order to study the influence of wind power grid connection on the small-signal stability of the multi-terminal VSC-HVDC system, based on the complete doubly-fed wind turbine model, damping characteristics of the multi-terminal VSC-HVDC system are qualitatively analyzed. Analyzed the influence of the doubly-fed induction generator (DFIG)-based wind turbine (WT) connection on the damping characteristics and stability of the multi-terminal VSC-HVDC system from multiple perspectives including the access point of the WT, the WT's capacity and transmission distance. The methods of the eigenvalue analysis and time-domain simulation analysis are adopted in this paper. Firstly, a complete three-terminal VSC-HVDC system model is built in PSCAD, and the systems after the WT connected to the grid are analyzed and compared. Then, based on the total least squares-estimation of signal parameters via rotational invariance techniques (TLS-ESPRIT) algorithm, some information of the system can be obtained such as eigenvalue, frequency, damping ratio and so on. The research results show that when the WT is connected to the inverter side, the damping ratio tends to be greater than connected to the rectifier side. In addition, within a certain range, as the capacity and transmission distance of the WT increase, the damping ratio also tends to increase. In this way, it provides a technical reference for the planning of wind farm access to multi-terminal VSC-HVDC system. [ABSTRACT FROM AUTHOR]

In the production of personalized, non-standard and trial products, orders are often single-piece or small-batch, and the processing parameters and BOM structure vary greatly between products. In such cases, it is necessary to consider processing and assembly in an integrated manner, and directly formulate flexible scheduling solutions according to the precedence constraints of BOM (PCB). To design such integrated scheduling method for personalized products with no-wait constraints (ISMPNC), firstly, a mathematical model considering both no-wait constraints and flexible machines is established, then, the event-based rescheduling rule (ERR) is used to deal with dynamic production tasks; finally, to solve the mathematical model, the artificial bee colony (ABC) algorithm with enhancements is proposed. Hence, a virtual grouping-based encoding method is designed to handle the precedence constraints when the number of no-wait predecessors is greater than one; a first-time-fit decoding method based on overlapping time is proposed to guarantee that no-wait operations always meet the precedence and no-wait constraints after decoding; a discrete differential equation based on the Hemming distance is proposed so that the ABC is capable of handling discrete encoding spaces; a neighborhood action based on key product moving is proposed and embedded into the ABC to enhance the local search capability. The operation research solver OR-Tools is used to verify the correctness of the mathematical model. The proposed ISMPNC considers both no-wait constraints and flexible machines, which is more realistic than the control method and could obtain a better scheduling scheme. [ABSTRACT FROM AUTHOR]

The hand foot, and mouth disease (HFMI)) epidemic has become a serious public health problem worldwide with a high economic and health burden. In addition, the prevalence of (HFMI) varies greatly between cities. Therefore, this paper aims to reveal high-risk cities for HFMD and associated meteorological and air pollution factors in Guangdong Province during 2014-2018. Data on the incidence of HFMD mid meteorological and air pollution. factors were obtained from the Guangdong Provincial Center for Disease Control and Prevention and Guangdong Meteorological Service. Three different grey incidence analysis (GIA) were used, namely Deng's grey incidence analysis, absolute degree of GIA, and second synthetic degree of GIA. Additionally, GMC (1,1) model was used to predict the trend of HFMD in 2019-2028. According to the second synthetic degree of GIA, the top three cities most affected by HFMD are Zhuhai, Guangzhou, and Foshan. However, the prediction model .found that the incidence of HFMD in Guangdong Province will generally decline in the next 10 years, indicating that the prevention and control measures are still relatively in place. Deng's grey incidence analysis found that CO, %O2, PM2.5, PM10), and wind scale are closely related to the incidence of HFMD. It is recommended to closely monitor weather change and urban air quality and take protective measures against HFMD in advance. The results of this study hare substantial implications for the control of HFMD. [ABSTRACT FROM AUTHOR]

A significant barrier to include population variability in risk assessment is our incomplete understanding of inter-individual variability and the differential susceptibility to environmental exposures induced adverse outcomes. By combining genome editing tools with the population diversity model, this article intended to highlight a potential strategy to identify and characterize the inter-individual variability factors, the determinant gene anchoring to a particular phenotype. The goal could be achieved by integrating the perturbed CRISPR-based unbiased functional genomics screening, genomewide or a focused subset of genes, in a population-based in vitro model system (such as the lymphoblastoid cell lines, LCL, available from HapMap and 1000 Genomes project). Then data can be translated to genetic variability and individual (or subpopulation) susceptibility by incorporating ethnicity and corresponding genome-wide association studies (GWAS) with functional genomics screening results. This approach can provide complementary data for next-generation risk assessment, in particular, for environmental stressors. The current paper outlined the previous work conducted with a population-based in vitro model system, perturbed CRISPR-based functional toxicogenomic screening of environmental chemicals, and finally, the potential strategies to combine these two platforms with their opportunities and challenges to achieve a mechanistic understanding of population variability. [ABSTRACT FROM AUTHOR]

The article presents a case of secretory carcinoma of the parotid gland in a 48-year-old male patient. It describes the ultrasonographic and pathological findings of the mass found behind the right ear of the patient. It also provides information on parotid secretory carcinomas, including treatment options.

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Objective: Paclitaxel (P) is a standard second-line chemotherapy in the treatment of advanced gastric cancer. This study compared the clinical outcome of a paclitaxel plus raltitrexed (RP) regimen as second-line treatment in metastatic gastric cancer (MGC) patients. Methods: An open, randomized, multi-center phase II clinical trial was conducted involving 148 patients who were randomly assigned and treated with RP [raltitrexed (3 mg/m2 on day 1) and paclitaxel (135 mg/m2 on day 1 every 3 weeks)] or P [paclitaxel (135 mg/m2 on day 1 every 3 weeks)] as 2nd-line chemotherapy. The primary endpoint was progression-free survival (PFS). The secondary endpoints were the overall response rate (ORR), overall survival (OS), and safety. Results: PFS had a tendency to be prolonged with RP compared to P (2.7 months vs. 1.7 months; P = 0.148). OS was also prolonged with RP compared to P (10.2 months vs. 6.1 months; P = 0.140). The ORR was equal in the RP and P groups (6.8% and 4.0%; P = 0.72). The disease control rate (DCR) in the RP and P groups was 56.2% and 36.0%, respectively. Grade 3-4 treatment-related adverse events occurred in 36.2% (RP) and 28.2% (P) of patients. Frequent grade 3-4 toxicities for RP and P were neutropenia (11.0% and 4.0%), anemia (1.4% and 4.0%), and thrombocytopenia (1.4% and 5.3%), and all grades of peripheral neurotoxicity (12.3% vs. 17.3%). All grades of hepatic toxicity were demonstrated for the RP and P groups based on elevated aminotransferase levels (27.4% and 14.1%). Subgroup analysis shows if MGC was combined with ascites or peritoneal involvement, the OS of the RP regimen was longer (P = 0.05). Conclusions: Second-line palliative chemotherapy with RP was shown to prolong the PFS and OS, especially among patients with ascites or peritoneal involvement, which warrants confirmation using larger sample studies. [ABSTRACT FROM AUTHOR]

Objective: To analyze the value of combined detection of tumor markers, neutrophil to lymphocyte ratio (NLR), D-dimer and T lymphocyte in the diagnosis of colon cancer. Methods: This is a retrospective study. A total of 80 patients with colon cancer and 80 patients with benign colon mass admitted to Baoding NO.1 Central Hospital from June 10, 2021 to December 10, 2022 were divided into the study group and the control group. Further comparison was performed on the tumor markers, NLR, D-dimer and T-lymphocyte levels between the two groups, associated with the comparison of corresponding levels of colon cancer at different stages. In addition, correlation analysis was carried out focusing on the above indicators with colon cancer. Results: Carcinoembryonic antigen (CEA), CA199, NLR, D-dimer and CD8+ cell count levels in the study group were significantly higher than those in the control group, while CD4+ cell count and CD4+/CD8+ ratio were obviously lower (P<0.05). Among I-IV colon cancer, the highest levels of CEA, CA199, NLR, D-dimer, CD4+ and CD4+/CD8+ ratio were found in patients with Stage-IV colon cancer, while the level of CD8+ was the lowest (P<0.05). Correlation analysis indicated that CEA, CA199, NLR, D-dimer and CD8+ were positively correlated with whether the patient had colon cancer (r=0.841, 747,991,889,565, all P<0.05), but negative correlations with CD4+ and CD4+/CD8+ ratio (r=-0.999, -0.994, all P<0.05). Conclusion: The detection of tumor markers combined with NLR, D-dimer and T-lymphocytes has reference value in the diagnosis of colon cancer. [ABSTRACT FROM AUTHOR]

Context: Paeonol (PAE) is the main phytochemical from Cortex Moutan. Its main pharmacological effects are anti-inflammatory and antioxidant, but its cardioprotective effect is unclear. Objective: The study investigates the effects and underlying mechanisms of PAE on transverse aortic constriction (TAC)-induced heart failure (HF) in mice. Materials and methods: C57BL/6 mice were randomly divided into five groups: sham, TAC, PAE10 (TAC + PAE 10 mg/kg), PAE20 (TAC + PAE 20 mg/kg) and PAE 50 (TAC + PAE 50 mg/kg). Paeonol was intragastrically administered to mice for 4 weeks. Mice were anaesthetized with pentobarbital sodium and underwent cardiac echocardiography using echocardiography system. Serum levels of atrial natriuretic peptide (ANP), tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were measured by enzyme-linked immunosorbent assay (ELISA). Myocardial apoptosis was detected with terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling (TUNEL) staining. Haematoxylin-eosin (H&E) and Masson's staining were used for histopathological evaluation. Western and quantitative real-time PCR (qRT-PCR) were performed to detect levels of apoptosis and fibrosis-related proteins. Results: Echocardiography showed PAE improved cardiac function (LVEF: TAC, 52.3±6.8%; PAE20, 65.8±3.6%; PAE50, 71.4±2.5%) and H&E staining showed PAE alleviated myocardial injury (TAC: 1170.3 ± 134.6 μm²; PAE50: 576.0 ± 53.5 μm²). Western and qRT-PCR results showed that PAE down-regulated the levels of ANP, BNP and α-MHC. In addition, TUNEL and western results showed PAE significantly inhibited apoptosis. Masson and western results showed PAE inhibited cardiac hypertrophy. Western results showed the ERK1/2/JNK pathway could be inhibited by PAE. Discussion and conclusions: Paeonol regulates ERK1/2/JNK to improve cardiac function, which provides theoretical support for the extensive clinical treatment of HF. [ABSTRACT FROM AUTHOR]

Myeloid lineage cells such as macrophages and dendritic cells (DCs), targeted by HIV-1, are important vehicles for virus dissemination through the body as well as viral reservoirs. Compared to activated lymphocytes, myeloid cells are collectively more resistant to HIV-1 infection. Here we report that NRP-1, encoding transmembrane protein neuropilin-1, is highly expressed in macrophages and DCs but not CD4+ T cells, serving as an anti-HIV factor to inhibit the infectivity of HIV-1 progeny virions. Silencing NRP-1 enhanced the transmission of HIV-1 in macrophages and DCs significantly and increased the infectivity of the virions produced by these cells. We further demonstrated that NRP-1 was packaged into the progeny virions to inhibit their ability to attach to target cells, thus reducing the infectivity of the virions. These data indicate that NRP-1 is a newly identified antiviral protein highly produced in both macrophages and DCs that inhibit HIV-1 infectivity; thus, NRP-1 may be a novel therapeutic strategy for the treatment of HIV-1 infection. [ABSTRACT FROM AUTHOR]

Objective • Heart failure with preserved ejection fraction (HFpEF) is a prevalent and clinically significant condition characterized by limited treatment options. In this context, the objective of this meta-analysis is to evaluate the effectiveness of sacubitril/valsartan compared to angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) in managing HFpEF. Methods • A systematic search of relevant studies was conducted in PubMed, Embase, Web of Science, and Cochrane Library. Randomized controlled trials comparing sacubitril/valsartan to ACEIs or ARBs in HFpEF patients were included. Inclusion criteria: LVEF>45%, NYHA II-IV, Sac/Val vs ACEI/ARB, RCTs, treatment duration >3 months, sample size ≥25 per group. Exclusion criteria: Animal studies, unclear/missing data, poor quality, case studies/expert opinions. Hospitalization for heart failure and cardiovascular mortality were the primary outcomes, while the additional results included mortality from all causes, improvement of NYHA class, modifications in NT-proBNP, and with LVEF. Results • Sacubitril/valsartan substantially reduced heart failure hospitalization rates compared to ACEIs and ARBs, according to a total of six studies involving 5,201 participants (Relative Risk, 0.78; 95% CI, 0.65 to 0.85; P = .001). Nonetheless, there were no significant improvements in mortality due to cardiovascular disease (Relative Risk, 0.94; 95% CI, 0.79-1.12; P = .563). Sacubitril/valsartan did not affect total mortality from all causes significantly (Relative Risk, 0.95; 95% CI, 0.84-1.09; P = .453), but it did enhance NYHA classification (Relative Risk, 1.25; 95% CI, 1.10-1.43; P = .001). NT-proBNP levels decreased substantially (Weighted Mean Difference, -266.67; 95% CI, -525.86 to -7.47), whereas there had been little major shift in LVEF (Weighted Mean Difference, 1.49; 95% CI, -1.33 to 4.21; P = .342). Conclusions • Sacubitril/valsartan may provide superior benefits in reducing heart failure hospitalization rates, NT-proBNP levels, and improving NYHA classification in patients with HFpEF compared to ACEIs and ARBs. Sacubitril/valsartan might be considered as a preferred treatment option for HFpEF patients due to its benefits in reducing heart failure hospitalization rates and improving symptom severity. [ABSTRACT FROM AUTHOR]

BACKGROUND: Iron deficiency anemia (IDA) is one of the commonest global nutritional deficiency diseases, and the low bioavailability of iron is a key contributing factor. The peptide-iron complex could be used as a novel iron supplement to improve iron bioavailability. RESULTS: In this study, antioxidant low molecular weight (<3 kDa) phosvitin peptide (named PP-4) was separated to prepare a phosvitin peptide-ferrous complex (named PP-4-Fe); then the structural conformation of PP-4-Fe was characterized and its bioavailability by in vitro digestion was evaluated. The results showed that PP-4 had good ferrous-binding activity with 96.14 ± 2.86 ~g Fe2+ mg-11, and had a strong antioxidant effect with 995.61 ± 79.75 ~mol TE mg-1 in 2,2'-azinobis'3-ethylbenzothiazoline- 6-sulfonic acid) (ABTS) and 62.3 ± 3.95 ~mol FeSO4 mg-1 in ferric ion reducing antioxidant power (FRAP). After ferrous binding, the FRAP activity of PP-4-Fe, enhanced by 1.8 times, formed a more ordered structure with an increase in α-helix and decrease in γ-random coil. The ferrous binding sites of PP-4 involved were the amino, carboxyl, imidazole, and phosphate groups. The PP-4-Fe complex displayed excellent gastrointestinal stability and antioxidant effects during digestion. The iron dialysis percentage of PP-4-Fe was 74.59% ± 0.68%, and increased to 81.10% ± 0.89% with the addition of 0.25 times vitamin C (VC). This indicated that PP-4-Fe displayed excellent bioavailability and VC in sufficient quantities had a synergistic effect on improving bioavailability. CONCLUSIONS: This study demonstrated that antioxidant phosvitin peptide was an efficient delivery system to protect ferrous ions and suggested that the phosvitin peptide-ferrous complex has strong potential as a ferrous supplement. [ABSTRACT FROM AUTHOR]

Fusobacterium nucleatum, an anaerobic Gram-negative bacterium primarily residing in the oral cavity, has garnered significant attention for its emerging role in cancer progression and prognosis. While extensive research has revealed mechanistic links between Fusobacterium nucleatum and colorectal cancer, a comprehensive review spanning its presence and metastatic implications in cancers beyond colorectal origin is conspicuously absent. This paper broadens our perspective from colorectal cancer to various malignancies associated with Fusobacterium nucleatum, including oral, pancreatic, esophageal, breast, and gastric cancers. Our central focus is to unravel the mechanisms governing Fusobacterium nucleatum colonization, initiation, and promotion of metastasis across diverse cancer types. Additionally, we explore Fusobacterium nucleatum's adverse impacts on cancer therapies, particularly within the domains of immunotherapy and chemotherapy. Furthermore, this paper underscores the clinical research significance of Fusobacterium nucleatum as a potential tumor biomarker and therapeutic target, offering a novel outlook on its applicability in cancer detection and prognostic assessment. [ABSTRACT FROM AUTHOR]

Purpose Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal malignancy that occurs primarily in children and adolescents. The clinical and pathological features of IMT in adult patients are not well understood. Materials and Methods We retrospectively searched for records of adult patients with IMT at Fudan University Shanghai Cancer Center from 2006 to 2021. Clinicopathological data, treatments, and outcomes were collected and analyzed. Results Thirty adult patients with IMT, mostly women (60.0%), were included. The median age of the patients was 38 (21-77). The most common primary site was abdominopelvic region (53.3%), followed by lungs (20.0%). Seven patients had an abdominal epithelioid inflammatory myofibroblast sarcoma (EIMS). The positivity rate of anaplastic lymphoma kinase (ALK) was 81.5% (22/27). Sixteen patients with advanced ALK-positive disease received crizotinib, with an objective response rate (ORR) of 81.3% and a disease control rate of 87.5%. The median progression-free survival was 20.8 months. EIMS was associated with more aggressive behavior; however, the prognosis was similar to that of non-EIMS patients after treatment with an ALK inhibitor. At a median follow-up time of 30 months (95% confidence interval [CI], 13.6 to 46.4), the 5-year overall survival was 77% (95% CI, 66 to 88) in all patients. Conclusion Adult IMTs appeared more aggressive, with a higher incidence of recurrence and metastases, and patients with EIMS had more aggressive cases. Treatment with ALK inhibitors resulted in a high ORR and a durable response, which suggested that ALK inhibitors could be used as a first-line treatment option in adult patients with ALK-positive advanced IMT. [ABSTRACT FROM AUTHOR]

Crystal monochromators are indispensable optical components for the majority of beamlines at synchrotron radiation facilities. Channel-cut monochromators are sometimes chosen to filter monochromatic X-ray beams by virtue of their ultrahigh angular stability. Nevertheless, high-accuracy polishing on the inner diffracting surfaces remains challenging, thus hampering their performance in preserving the coherence or wavefront of the photon beam. Herein, a magnetically controlled chemical-mechanical polishing (MC-CMP) approach has been successfully developed for fine polishing of the inner surfaces of channel-cut crystals. This MC-CMP process relieves the constraints of narrow working space dictated by small offset requirements and achieves near-perfect polishing on the surface of the crystals. Using this method, a high-quality surface with roughness of 0.614 nm (root mean square, r.m.s.) is obtained in a channelcut crystal with 7 mm gap designed for beamlines at the High Energy Photon Source, a fourth-generation synchrotron radiation source under construction. On-line X-ray topography and rocking-curve measurements indicate that the stress residual layer on the crystal surface was removed. Firstly, the measured rocking-curve width is in good agreement with the theoretical value. Secondly, the peak reflectivity is very close to theoretical values. Thirdly, topographic images of the optics after polishing were uniform without any speckle or scratches. Only a nearly 2.5 nm-thick SiO2 layer was observed on the perfect crystalline matrix from high-resolution transmission electron microscopy photographs, indicating that the structure of the bulk material is defect- and dislocation-free. Future development of MC-CMP is promising for fabricating wavefront-preserving and ultra-stable channel-cut monochromators, which are crucial to exploit the merits of fourth-generation synchrotron radiation sources or hard X-ray free-electron lasers. [ABSTRACT FROM AUTHOR]

Objective: In this study, we aim to investigate the safety and feasibility of robot-assisted kidney transplantation (RAKT) in children by reporting our initial experience. Methods: Using the Da Vinci robotic system, we performed a successful RAKT on a 12-year-old child who had been on hemodialysis for 27 months. Results: The total operative time for the RAKT procedure was 245 min. The vascular anastomosis took 41 min, while the ureterovesical anastomosis lasted 18 min. The estimated blood loss during the surgery was 100.0 ml. Following the removal of the arterial and venous clamp, the kidney was well perfused, and no perioperative complications were observed. Conclusion: This study presents the first pediatric RAKT in China, proving the safety and feasibility of the robotassisted technique for children awaiting kidney transplantation. [ABSTRACT FROM AUTHOR]

Voltage source converter-based multi-terminal high-voltage direct current (VSC-MTDC) transmission system can realize a multi-point power supply, multi-drop power receiving, and mutual coordination between the converter stations to ensure the reliability of the transmission. Based on the PSCAD/EMTDC platform, a five-terminal DC transmission system model is established. According to the fast power regulation capability and overload capacity of the VSC-MTDC power transmission system, an analysis of additional emergency power support for a transmission system under large disturbance conditions was carried out. A new control strategy for emergency power support that introduces its basic principle is proposed in this paper. It uses the short-term overload capability of the DC system. By changing the power reserve of the converter station and the electrical distance between the converter stations, the influence of the power reserve and the electrical distance on the emergency power supply guarantee is analyzed the stability of the system is improved, thereby improving the sudden change of power caused by voltage fluctuations, and the feasibility of the control module is verified by PSCAD simulation. The simulation results show that when the system power supply suddenly changes, the converter stations at a short distance and large power reserve has a better effect on emergency power supply protection. A comparative study of the active power support of a single converter station and multiple converter stations is carried out. The research results show that the use of emergency power [ABSTRACT FROM AUTHOR]

A wire mesh liner possesses a better acoustic linearity to high sound pressure level (SPL) than a perforated liner, but lacks an accurate impedance model. Thus, its nonlinear effect due to high SPL is studied in this paper. A jet simulation of mesh orifices (two-dimensional slits) is conducted. It reveals that an approximation to the nonlinear loss in an existing model ("A Model for the Acoustic Impedance of Linear Suppressor Materials Bonded on Perforated Plate," AIAA Paper 1981-1999, Oct. 1981) includes implicitly linear loss and neglects the effect of the orifice distribution uniformity, and so the nonlinearity of distributed micro-orifices is overestimated. This accords with the experimental result in an impedance tube that the high-SPL resistance is overestimated for a fine mesh. Meanwhile, it is indicated that the discharge coefficient is overestimated in the existing model for neglecting the vena contracta at least at the maximum jet of a coarse mesh, and so the high-SPL resistance is underestimated. Therefore, the nonlinear loss factor Fnl is defined herein to exclude the linear loss and avoid the deviation from the jet contracta of the mesh, which presents a better prediction. Finally, an empirical relation of Fnl considering the orifice diameter and a correction to the reactance are given experimentally, and thus, a more accurate impedance model of the wire mesh liner is established. [ABSTRACT FROM AUTHOR]

The characteristics, formation mechanisms, and influences on physical properties of carbonate minerals in shale reservoirs of Wufeng-Longmaxi formations in Sichuan Basin are systematically investigated by utilizing electron probe microscope with spectrometer and energy spectrometer, combined with physical properties and whole rock X-diffraction and organic carbon data. The research yielded the findings that follow: First, the main carbonate minerals are calcite, dolomite, and ferriferous dolomite. Calcite is a single mineral that fills the siliceous shell cavity of radiolarians and exists between mineral particles. Ferriferous dolomite always rings dolomite, which is a single mineral that is present among mineral particles and aggregates. Second, calcite is produced by microorganisms that secrete calcium carbonate in the surface of seawater. The siliceous skeleton cavity of radiolarian and seawater both precipitate calcite, which partially dissolves while settling in seawater before depositing on the seabed and being preserved by burial. Thirdly, the dolomite is a diagenetic mineral formed on the water-sediment interface with physiological activities of sulfate bacteria, and the ferriferous dolomite is produced by methanogenic metabolism during the initial burial of muddy sediments. Fourthly, organic carbon, pyrite, quartz, and clay minerals are closely related to reservoir physical properties, while carbonate has no effect on porosity and permeability as a whole. Future research on shale reservoir diagenesis should make use of the in-situ detection and element area scanning, in particular with the spectrogram from electron probe microscope technology, which provides typical petrological evidences for the study of characteristics, formation mechanism, and influence on physical properties of carbonate minerals in shale reservoirs. [ABSTRACT FROM AUTHOR]

The flowback rate of a shale gas well is controlled by many factors, such as geological and engineering factors, which have a certain complexity. For the aforementioned reason, the knowledge-driven method often has difficulty effectively capturing the correlation rules among multiple datasets. As a data-driven algorithm, deep learning has strong advantages in data correlation analysis, nonlinear fitting and other applications. In this paper, an algorithm is set up to forecast the shale gas well flowback rate by using a deep learning algorithm based on the flowback characteristic factors and data from 286 shale gas wells in the Weiyuan field. An algorithm and prediction model of the flowback parameters of the Weiyuan shale gas wells is established to effectively capture their flowback characteristics. First, the general situation of the study area is briefly introduced, and the data used to predict the flowback rate in this area are analyzed. Second, based on the deep learning algorithm, two kinds of deep feedforward neural network structures and a neural network-based prediction method of shale gas well flowback rate are designed. Finally, according to the regional data, the prediction and analysis of the flowback rate of Weiyuan shale gas wells are carried out. The results show that the correlations between 17 factors, such as fracturing section length and shale gas well flowback rate, are not obvious, but that the deep learning method proposed in this paper can effectively and accurately capture the correlations between the data and predict the flowback rate. The results show high accuracy. • An approach of Shale gas well flowback rate prediction based on a deep learning algorithm is designed. • Two kinds of deep feedforward neural network structures for shale gas well flowback rate prediction are designed. • The flowback rate of Weiyuan shale gas wells are carried out using proposed algorithm. [ABSTRACT FROM AUTHOR]

The article presents a research report on membraneless organelles formed by liquid-liquid phase separation increase bacterial fitness. Topics include metastable liquid-structured protein assemblies increase bacterial fitness by enabling cells to tolerate environmental stresses; and quantitative agreement with phase-separated liquid droplet formation driven by interacting proteins under thermal equilibrium that nucleate following diffusive collisions in the cytoplasm.

At present, there are many problems in coal mine operation, such as formation of large amounts of dust, complex dust migration behavior, severe respiratory harm, poor on-site performance of spray dust removal technology under windy conditions, and low collection efficiency of respirable dust. To solve the above problems, the finite element method of computational fluid dynamics (CFD) was used. The Spalart-Allmaras turbulence model of COMSOL software and the tracking module for atomized particles broken by droplets were used. They were combined with the Fraunhofer diffraction principle to study the distributions of the velocity of the airflow field, droplet size, droplet velocity and wind resistance for a supersonic water siphonic atomization device. The influence of the above factors on dust removal at different aerodynamic pressures was studied experimentally. The relationships between spray characteristics, flow field velocity distribution, dust removal effect and spray characteristics were revealed. The research showed that with increasing pressure, the supersonic component accounted for an increased proportion of the flow field inside the nozzle, average velocity of the flow field increased, atomization efficiency increased, droplet particle size decreased, and droplet velocity increased. The particle size of the droplets first increased, then decreased and then increased with increasing spraying distance. Additionally, the range of high-speed fine droplet size fog increased with increasing pressure. At the same transverse wind speed, with increasing pressure, the deflection point of the fog field moved backward, and the wind resistance of the spray was enhanced. With the increase in aerodynamic pressure, the dust isolation and negative pressure effect of spray and the dust collection efficiency increased, and there was an optimal value for dust removal in a limited space. The reason was that when the pressure increased to a certain extent, the air flow reversed in the coil at the bottom of the limited space, which blew the dust that was not aggregated at the bottom away from the area where dust was falling. Thus, the dust was entrained in fog droplets but could not be removed from the air flow. The dust dispersion in the air flow after purification differed greatly at different pressures because the removal efficiency of dust in the 2.5–10 μm particle size range was mainly affected by the pressure. In a field study of a fully mechanized mining face, the fog curtain formed by the device covered the whole section under the condition of airflow disturbance with large transverse velocity, and the comprehensive respirable dust removal efficiency of the working area reached 92.3%. Thus, this method showed good wind resistance and dust removal performance. The study of this technology can provide a clean working environment and theoretical guidance for the safe production of coal in the future, especially for fully mechanized mining faces. [Display omitted] • The transonic flow field distribution has significant influence on the supersonic atomization effect. • The droplet size of supersonic atomization does not always increase with the increase of jet distance. • The increase of aerodynamic pressure is conducive to the resistance of droplets to ambient airflow disturbance. • The trapping characteristics of dust do not depend on the droplet size. • The dust of 2.5–10 μm in the fully mechanized mining face of coal mine is efficiently removed. [ABSTRACT FROM AUTHOR]