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  • 1
    In: Energies, MDPI AG, Vol. 14, No. 16 ( 2021-08-22), p. 5193-
    Abstract: In order to solve the problems of roadway stability and easy instability under repeated mining of close-distance coal seam groups, the mechanism and control technology of surrounding rock instability under repeated mining were studied via indoor testing, field testing, physical similarity simulation experiment, and numerical simulation. The results show that the surrounding rock of roadway has low strength, low bearing capacity, and poor self-stabilization ability, and it is vulnerable to engineering disturbances and fragmentation. Affected by the disturbance under repeated mining, the roadway surrounding rock cracks are developed and the sensitivity is strong, and it is prone to large-scale loose and destroyed. The location of the roadway is unreasonable, and the maximum principal stress of the roadway is 3.1 times of the minimum principal stress, which is quite different. Thus, under a large horizontal stress, the surrounding rock undergoes long-range expansion deformation. On the basis of this research, the direction and emphasis of stability control of roadway surrounding rock under repeated mining of coal seam groups in close-distance are shown. A repair scheme (i.e., long bolt + high-strength anchor cable + U-shaped steel + grouting) is proposed, and reduces the risk of roadway instability.
    Type of Medium: Online Resource
    ISSN: 1996-1073
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2437446-5
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  • 2
    In: Animal Nutrition, Elsevier BV, Vol. 16 ( 2024-03), p. 306-312
    Type of Medium: Online Resource
    ISSN: 2405-6545
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2024
    detail.hit.zdb_id: 2834745-6
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  • 3
    Online Resource
    Online Resource
    EDP Sciences ; 2021
    In:  E3S Web of Conferences Vol. 261 ( 2021), p. 01067-
    In: E3S Web of Conferences, EDP Sciences, Vol. 261 ( 2021), p. 01067-
    Abstract: The fault estimation of robot joint is of great significance to improve the reliability and stability of robot joint. Based on the design of fault diagnosis observer and the finite frequency theory, a method of H infinite fault estimation with frequency domain is proposed. The design method combines H infinite filter wave with finite frequency technology effectively, and has strong anti-interference performance, Compared with other design methods, the method proposed in this paper can improve the accuracy of fault estimation
    Type of Medium: Online Resource
    ISSN: 2267-1242
    Language: English
    Publisher: EDP Sciences
    Publication Date: 2021
    detail.hit.zdb_id: 2755680-3
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  • 4
    Online Resource
    Online Resource
    MDPI AG ; 2021
    In:  International Journal of Molecular Sciences Vol. 22, No. 15 ( 2021-07-30), p. 8212-
    In: International Journal of Molecular Sciences, MDPI AG, Vol. 22, No. 15 ( 2021-07-30), p. 8212-
    Abstract: Inhibition of ruminal microbial urease is of particular interest due to its crucial role in regulating urea-N utilization efficiency and nitrogen pollution in the livestock industry. Acetohydroxamic acid (AHA) is currently the only commercially available urease inhibitor, but it has adverse side effects. The urease accessory protein UreG, which facilitates the functional incorporation of the urease nickel metallocentre, has been proposed in developing urease inhibitor through disrupting urease maturation. The objective of this study was to screen natural compounds as potential urease inhibitors by targeting UreG in a predominant ruminal microbial urease. In silico screening and in vitro tests for potential inhibitors were performed using molecular docking and an assay for the GTPase activity of UreG. Chelerythrine chloride was selected as a potential urease inhibitor of UreG with an inhibition concentration IC50 value of 18.13 μM. It exhibited mixed inhibition, with the Ki value being 26.28 μM. We further explored its inhibition mechanism using isothermal titration calorimetry (ITC) and circular dichroism (CD) spectroscopy, and we found that chelerythrine chloride inhibited the binding of nickel to UreG and induced changes in the secondary structure, especially the α-helix and β-sheet of UreG. Chelerythrine chloride formed a pi-anion interaction with the Asp41 residue of UreG, which is an important residue in initiating the conformational changes of UreG. In conclusion, chelerythrine chloride exhibited a potential inhibitory effect on urease, which provided new evidence for strategies to develop novel urease inhibitors targeting UreG to reduce nitrogen excretion from ruminants.
    Type of Medium: Online Resource
    ISSN: 1422-0067
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2019364-6
    SSG: 12
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  • 5
    Online Resource
    Online Resource
    MDPI AG ; 2021
    In:  Mathematics Vol. 9, No. 17 ( 2021-08-27), p. 2072-
    In: Mathematics, MDPI AG, Vol. 9, No. 17 ( 2021-08-27), p. 2072-
    Abstract: Roof accidents seriously affect the safe and efficient mining of the working faces. Therefore, it is necessary to assess and identify the possible and influencing factors on the occurrence of roof risk in a fully mechanized mining workface. In this study, based on the analytic hierarchy process and fuzzy comprehensive evaluation, a comprehensive standard cloud model was established through constructing a quantitative grade interval and calculating the weight of each index to achieve the aim of a roof risk assessment and identification. The accuracy of risk assessment was ensured by using the comprehensive analyses of various aspects, such as cloud digital features, risk assessment cloud image and standard cloud image. This showed that the main influencing factors on the occurrence of roof accidents were roof separation distance, weighting intensity and rib spalling followed by the coal body stress concentration, initial support force and geological conditions. Taking 42,115 fully mechanized working faces in the Yushen coal mining area as an engineering background, this model was adopted to assess and identify the risk of roof accidents through generating comprehensive assessment cloud images and introducing the Dice coefficient to calculate the similarity degree. The results showed that the overall risk of roof accidents in 42,115 working faces was regarded as grade II (general risk) through the overall index of comprehensive risk evaluation and a similarity degree of 0.8606. The impact of roof condition was mainly influenced by the risk of roof accidents, while the support status, personal working status and coal body condition had a limited effect on the risk of roof accidents. The comprehensive standard cloud model proposed in this study had strong visibility and discovered the key parts of risk indexes easily to solve the problems of ambiguity and quantitative identification in traditional roof risk evaluation methods. Therefore, this model was worth promoting, because it laid the foundation for the intelligent identification and early warning system of roof accident risk in a fully mechanized mining workface.
    Type of Medium: Online Resource
    ISSN: 2227-7390
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2704244-3
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  • 6
    In: Mathematics, MDPI AG, Vol. 10, No. 13 ( 2022-06-21), p. 2166-
    Abstract: In this study, taking the Sheng’an coal mine as an engineering background, the failure characteristics of the surrounding rock of a roadway under repeated mining in a close-distance coal seam is comprehensively illustrated through field measurements (e.g., drilling imaging), theory analysis and numerical simulation (finite difference method (FDM)). The results show that although the return airway 10905 remains intact, the apparent failure of the roadway’s roof and the coal pillar can be observed. In addition, the expression of floor failure depth caused by upper coal seam mining is obtained through elastic-plastic theory. Meanwhile, the deformation of the surrounding rock of the roadway increases with the increase of repeated mining times, especially for the horizontal displacement of the roadway on the coal pillar side. Moreover, the cracks’ evolution of surrounding rock in the roadway can be observed as asymmetric characteristics. Finally, the stability control technology of “asymmetric anchor net cable + I-steel” is proposed to prevent potential mining disasters, and the feasibility of this support scheme is verified by numerical simulation and field practices. It can meet the requirement of safe mining and provide guidelines to effectively solve the failure of a roadway in close-distance coal seam mining.
    Type of Medium: Online Resource
    ISSN: 2227-7390
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2704244-3
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  • 7
    Online Resource
    Online Resource
    American Society of Clinical Oncology (ASCO) ; 2023
    In:  Journal of Clinical Oncology Vol. 41, No. 16_suppl ( 2023-06-01), p. e16085-e16085
    In: Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 41, No. 16_suppl ( 2023-06-01), p. e16085-e16085
    Abstract: e16085 Background: Patients with esophageal cancer benefited from neoadjuvant chemotherapy combined with immunotherapy. However, the sequence of administration during neoadjuvant therapy remains under considerable debate. Methods: A study on 23 enrolled patients with esophageal cancer who received 2 cycles of neoadjuvant treatment of dose-limiting chemotherapy combined with sequential pembrolizumab and 2 cycles of adjuvant treatment of dose-limiting chemotherapy combined with sequential pembrolizumab was carried out. Serial plasma samples were collected and subjected to T cell receptor (TCR) sequencing. Tissues with pre- and post-neoadjuvant therapy were obtained and performed with whole-exome sequencing and transcriptome sequencing. Results: After neoadjuvant therapy, the percentage of patients with a pathological major response (MPR) was 39.1% (9/23), consisting of 21.7% (5/23) completed pathological response (cPR). TCR sequencing analysis showed that the peripheral blood-dominated TCR clones significantly augmented during the neoadjuvant treatment. Tumor mutational burden (TMB) was higher in the MPR group than in the non-MPR group at baseline. In addition, infiltrating CD8+ T cells increased and regulatory T (Treg) cells decreased in the MPR group after neoadjuvant therapy. While Treg cells increased in the non-MPR group after neoadjuvant treatment. Conclusions: Dominated TCR clones increased during the neoadjuvant limited-dose chemotherapy stage, which would contribute to sequential PD-1 blockade. Additionally, TMB, CD8+ T cells, and Treg cells are associated with clinical benefits during treatment.
    Type of Medium: Online Resource
    ISSN: 0732-183X , 1527-7755
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Clinical Oncology (ASCO)
    Publication Date: 2023
    detail.hit.zdb_id: 2005181-5
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  • 8
    Online Resource
    Online Resource
    American Society of Clinical Oncology (ASCO) ; 2023
    In:  Journal of Clinical Oncology Vol. 41, No. 16_suppl ( 2023-06-01), p. e16081-e16081
    In: Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 41, No. 16_suppl ( 2023-06-01), p. e16081-e16081
    Abstract: e16081 Background: Immunotherapy plus chemotherapy has shown benefits for locally advanced esophageal squamous cell carcinoma (ESCC). However, the optimal dose, administration interval, and sequence between chemotherapy and immune checkpoint inhibitor are still elusive. In this study, we prospectively analyzed the efficacy and safety of modified chemotherapy followed by anti-programmed cell death protein 1 as perioperative therapy for stage II/IIIA ESCC. Methods: Patients with stage II/IIIA esophageal squamous cell carcinoma were eligible for this study. The patients were treated with 2 cycles of attenuated nab-paclitaxel and cisplatin (180-220mg/m2 for nab-paclitaxel, 60 mg/m2 for cisplatin) on day one and pembrolizumab (200 mg for patients weighted ≥60kg or 100 mg for patients weighted 〈 60kg) delayed on day five every 3 weeks. Subsequently, the patients received surgery four to six weeks after the second cycle treatment followed by 2 more cycles of treatments. The primary endpoints were major pathological response rate (MPR), and the second endpoints were pathological complete response rate (pCR), DFS, safety, R0 resection rate, and OS. The last follow-up time was January 31st, 2023. Results: A total of 23 patients were enrolled in our study and received whole 4 cycles of perioperative treatment. Of the whole patients, the mean age was 57.5. The median follow-up time was 19.2 months (range: 4.1-30.1). All patients underwent surgery and received R0 resection after 2 cycles of neoadjuvant attenuated chemotherapy plus delayed pembrolizumab. Down-stage was achieved in 9 of 21 (42.8%) patients with confirmed stage pre- and post- surgery. The MPR rate was 43.5%, and pCR rate was 26.1%. Up to the last follow-up, 1 patient reported death due to brain metastases, and 4 patients experienced disease progression. The median DFS and OS were not reached. The rates of one-year DFS and OS were 88.2% (15/17) and 94.4% (17/18) respectively. 21 patients (95.5%) reported treatment-related adverse events (TRAEs), most of which were grade 1-2. Two patients reported grade 3 leukopenia, and 1 patient reported grade 4 elevated transaminases and discontinued immunotherapy after surgery. The most common TRAEs were nausea (59.1%), rash (36.4%), asthenia or fatigue (31.8%), and leukopenia (27.3%). Conclusions: Our study suggested that modified nab-paclitaxel and cisplatin followed by delayed pembrolizumab as perioperative treatment was effective and well tolerated for locally advanced ESCC. Clinical trial information: ChiCTR2000034925 . [Table: see text]
    Type of Medium: Online Resource
    ISSN: 0732-183X , 1527-7755
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Clinical Oncology (ASCO)
    Publication Date: 2023
    detail.hit.zdb_id: 2005181-5
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  • 9
    Online Resource
    Online Resource
    MDPI AG ; 2020
    In:  Electronics Vol. 9, No. 8 ( 2020-08-04), p. 1251-
    In: Electronics, MDPI AG, Vol. 9, No. 8 ( 2020-08-04), p. 1251-
    Abstract: This paper presents an open-circuit (OC) fault diagnosis method of three-phase voltage-source inverters (VSIs) for permanent magnet synchronous motor (PMSM) drive systems based on the hybrid system model (HSM). On the basis of phase voltage analysis, the HSM of the PMSM-inverter system was established, which can describe the system more accurately. To quickly diagnose whether the fault occurs, a current estimator was constructed based on the healthy HSM. Different fault types of the VSI can be simulated synchronously by the HSM, and the similarity between each simulated fault type and the actual one is evaluated based on the Euclidean distance method. Therefore, the fault isolation can be carried out according to the characteristics of Euclidean distances. The proposed method has the advantages of fast diagnosis speed and strong robustness, and it does not require additional sensors. By the presented diagnosis algorithm, the fault can be detected and isolated within a time interval about 5% and 10% of the current fundamental wave period, respectively. The simulation and experimental results verify the effectiveness of the proposed method.
    Type of Medium: Online Resource
    ISSN: 2079-9292
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2662127-7
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  • 10
    Online Resource
    Online Resource
    MDPI AG ; 2022
    In:  International Journal of Molecular Sciences Vol. 23, No. 2 ( 2022-01-13), p. 817-
    In: International Journal of Molecular Sciences, MDPI AG, Vol. 23, No. 2 ( 2022-01-13), p. 817-
    Abstract: Regulation of microbial urease activity plays a crucial role in improving the utilization efficiency of urea and reducing nitrogen emissions to the environment for ruminant animals. Dealing with the diversity of microbial urease and identifying highly active urease as the target is the key for future regulation. However, the identification of active urease in the rumen is currently limited due to large numbers of uncultured microorganisms. In the present study, we describe an activity- and enrichment-based metaproteomic analysis as an approach for the discovery of highly active urease from the rumen microbiota of cattle. We conducted an optimization method of protein extraction and purification to obtain higher urease activity protein. Cryomilling was the best choice among the six applied protein extraction methods (ultrasonication, bead beating, cryomilling, high-pressure press, freeze-thawing, and protein extraction kit) for obtaining protein with high urease activity. The extracted protein by cryomilling was further enriched through gel filtration chromatography to obtain the fraction with the highest urease activity. Then, by using SDS-PAGE, the gel band including urease was excised and analyzed using LC-MS/MS, searching against a metagenome-derived protein database. Finally, we identified six microbial active ureases from 2225 rumen proteins, and the identified ureases were homologous to those of Fibrobacter and Treponema. Moreover, by comparing the 3D protein structures of the identified ureases and known ureases, we found that the residues in the β-turn of flap regions were nonconserved, which might be crucial in influencing the flexibility of flap regions and urease activity. In conclusion, the active urease from rumen microbes was identified by the approach of activity- and enrichment-based metaproteomics, which provides the target for designing a novel efficient urease inhibitor to regulate rumen microbial urease activity.
    Type of Medium: Online Resource
    ISSN: 1422-0067
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2019364-6
    SSG: 12
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