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Due to the fluctuation of PV power, it is difficult to keep the active power of the PV grid-connected inverter constant. To address the above problems, this paper proposed a new three-level integrated photovoltaic storage machine consisting of a T-type three-level DC/AC converter, a three-level Boost converter and a three-level bi-directional DC/DC converter and related control strategies. The three-level structure allowed for lower switching losses resulting in higher system efficiency and wider voltage range adaptability. In terms of control, frequency differentiation and deviation control were introduced in the control of the energy storage DC/DC converter to achieve frequency regulation of the transient/static support of the active power of the parallel network. The simulation and experiment show that when the frequency fluctuation range is 50.02~49.97 Hz (meeting the national standard), the new optical storage all-in-one machine proposed in this paper can operate stably and be easily realized.

ObjectiveTo investigate the biological function and molecular mechanism of long non-coding RNA Linc‑pint in colorectal cancer.MethodsQuantitative real‑time quantitative （qRT‑PCR） was performed to detect the expression level of Linc‑pint in 31 pairs of colorectal cancer tumor and adjacent normal tissues； correlation between the expression level of Linc‑pint and the clinicopathological characteristics was analyzed by the chi‑square test. Kaplan-Meier survival analysis was used to assess the relationship between Linc‑pint expression level and the prognosis of patients. Cox regression model was used to analyze the relationship between clinicopathological characteristics and the prognosis of patients. Expression level of Linc‑pint were detected by qRT‑PCR in 5 common colorectal cancer cell lines. Effect of Linc‑pint on cell proliferation， invasion and migration was measured by cell counting kit‑8 assay， Transwell assay and harvested xenografts from nude mice. qRT‑PCR was performed to detect the expression level of Linc‑pint's target gene micro RNA（miR）‑21 in 31 pairs of colorectal cancer tumor tissues and adjacent normal tissues. Pearson correlation coefficient was used to assess the correlation between Linc‑pint and miR‑21. qRT‑PCR was used to detect the expression of overexpression of Linc‑pint on miR‑21 in colorectal cancer cells.ResultsExpression level of Linc‑pint in normal tissues （3.95±1.16） was significantly higher than that in colorectal cancer tissues （2.74±0.95） （t=6.17， P

A laser welding with wire filler feeding was developed to replace traditional arc welding process for joining aluminium alloy railcar body components. A three-dimensional (3D) thermo-elastic-plastic finite element (FE) model was applied to compute the plastic strains of weld zone in a downsized aluminium alloy plate with butt-joint, T-joint and fillet-joint configurations, respectively, combined with corresponding experimental validations. The achieved plastic strains at the weld zone were then input as inherent strain loadings into elastic structural FE model of fully sized aluminium alloy railcar body components to predict the welding induced distortion with the experimentally measured out-of-plane distortions. The experimentally validated FE model was then further applied for optimizing the inverse pre-deformation of plates to counteract the welding induced deformation, finally to mitigate the welding distortion issues. [ABSTRACT FROM AUTHOR]

Antimicrobial therapy remains one of the major global challenges, particularly in the absence of effective treatment strategies for drug‐resistant bacteria. In this study, a comprehensive treatment approach is proposed for drug‐resistant bacterial wound infections based on the development of thermal‐cascade multifunctional therapeutic systems (MTSs), spanning from the design of functional nanoscale materials to macroscopic smart hydrogel. Within the MTSs, functional antibiotic‐loaded hybrid nanoclusters enable targeted therapeutic delivery and synergistic mild hyperthermia‐antibiotic treatment, strongly suppressing drug‐resistant bacteria while demonstrating excellent biocompatibility with normal cells and tissues. Furthermore, near‐infrared irradiation can trigger the photothermal effects of hybrid nanoclusters to induce gelation of thermal‐sensitive hydrogel, forming MTSs to serve as highly adaptable, drug‐enriched protective dressings for infected wounds. Both in vitro and in vivo results substantiate that MTSs enhance the bioavailability of therapeutic agents (including bacterial internalization and tissue penetration), exert synergistic effects to completely eradicate drug‐resistant bacteria, promoted wound healing and revascularization, and demonstrate excellent biocompatibility. This work offers an innovative demonstration to address drug‐resistant bacterial infections through the advancement of sophisticated material systems. [ABSTRACT FROM AUTHOR]

Objective: To explore the risk factors for inferior vena cava filter (IVCF) thrombus in orthopedic trauma patients who underwent filter placement with ongoing anticoagulation in clinical settings. Methods: We retrospectively analyzed clinical data from fracture patients with lower extremity acute deep vein thrombosis (DVT) implanted with an IVCF admitted to Tianjin Hospital from January 2017 to December 2019. Potential risk factors, such as gender, age, diabetes, hypertension, fracture sites, thrombus location, free-floating thrombus, filter type, Injury Severity Score (ISS), and postoperative D-dimer values, were analyzed by the Chi-square test, t-test, logistic regression, and receiver operating characteristic (ROC) curve analysis. Results: A total of 662 patients were included in our study, and filter-related thrombosis was present in 67 (10.1%) patients. No significant differences were observed in age, gender, hypertension, diabetes, fracture site, free-floating thrombus, filter type, indwelling time, and postoperative D-dimer level. Thrombus location and ISS were significantly different (p < 0.05). Popliteal DVT (P-DVT) (odds ratio [OR]: 2.130, p = 0.018) and ISS (OR: 1.135, p = 0.000) were associated with filter thrombus. Patients with P-DVT were prone to a small filter thrombus (OR: 3.231, p = 0.037). From the ROC curve analysis, the diagnostic value of ISS was 24.5 and 26.5 for patients with filter and massive filter thrombus, respectively. Conclusion: Thrombus location and ISS were independent risk factors for filter thrombus in patients with traumatic fractures. P-DVT had a higher potential to result in a small filter thrombus and an ISS value >26.5, which was considered a significant massive filter thrombus predictor. [ABSTRACT FROM AUTHOR]