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Owing to the challenges of unstable generation and random load disturbance in new energy power system, this paper integrates the battery energy storage model into the traditional load frequency control (LFC) framework, and proposes a LFC scheme based on adaptive global sliding mode control to stabilize the frequency of power systems amid unpredictable load frequency deviation. First of all, the nonlinear time-varying function is added to the sliding mode surface to make the system globally robust. Then, an adaptive sliding mode control law is crafted to dynamically adjust the frequency variations caused by random load disturbance. Moreover, by utilizing the improved Lyapunov function and Bessel-Legendre inequality, the stabilization criteria of multi-area interconnected power system are built. Finally, the efficacy of the proposed method is demonstrated through single and double area LFC simulation experiments with the common system parameters.

Objective To evaluate the effect of flipped classrooms combined with case-based collaborative learning (CBCL) in teaching internal medicine in the experimental eight-year medical doctor program[new academic '4+4' pilot class(NAPC)]. Methods Medical students from the class 2019 and class 2020 of NAPC in Peking Union Medical College were selected as the objects. A teaching method of flipped classroom combined with CBCL was applied in the course of internal medicine (inflammatory bowel disease). Through the knowledge test before and after class discussion, the students' mastery of relevant knowledge was evaluated, and the Likert scale was used to give quantitative feedback on the teaching effect. Results A total of 45 medical students from NAPC were enrolled, including 20 students from class 2019 and 25 students from class 2020.A total of 42 students completed the knowledge test before class and 45 students completed the knowledge test after class.After the flipped classroom combined with CBCL, the students' correct answer rate had significantly increased on questions about the age of inflammatory bowel disease onset, severity of ulcerative colitis endoscopy, lesion range, differential diagnosis, treatment principles, clinical manifestations of Crohn's disease, and treatment principles(all P < 0.001); the median correct answer rate of all questions significantly increased [33.3(26.2, 85.7)% vs. 93.3(71.1, 95.6)%, P=0.001]. Thirty students(66.7%, 30/45)completed the post-class feedback; the overall satisfaction score of the teaching mode of flipped classroom was (4.00±0.74) points. Conclusions The teaching mode of flipped classroom combined with CBCL can significantly improve learning outcome in medical students of the experimental eight-year program. Students are generally satisfied with the teaching mode.

Serum pepsinogen (PG) is a good indicator of atrophic changes in the gastric mucosa. Gastric mucosal atrophy is a high-risk factor for gastric cancer. Serological testing for PG combined with endoscopy can help to improve gastric cancer screening. In this study, we established the reference ranges of serum PG-I, PG-II, and the PG-I/II ratio (PGR) in the Chinese population by chemiluminescence immunoassay (CLIA) and enzyme-linked immunosorbent assay (ELISA). Besides, in the real world, doctors are often confused by the results of different testing platforms. Thus, a comparison of methods CLIA and ELISA was performed. Methods: 2904 individuals were enrolled from six regions in China as part of the Chinese Adult Digestive Diseases Surveillance (2016) program. The individuals completed questionnaires and volunteered to undergo examinations, including gastroscopy, urea breath test, abdominal ultrasound examination and routine serologic tests. Serum was collected to measure PGs (including PG-I, PG-II and PGR) by CLIA and ELISA. Participants who were found obvious abnormalities or absent from the examinations were excluded. Ultimately, 747 healthy individuals were enrolled in this study. The Kolmogorov–Smirnov test was used to assess the distribution of variables. The Kruskal–Wallis H or Mann–Whitney U-tests were used to compare different sex, age, and geographical groups. The 95% reference ranges of PGs obtained by the two methods were established according to document CLSI-EP28-A3, with covariates of sex, age, and region. Spearman correlation analysis, linear regression analysis and allowable total error (ATE) zone analysis were utilized for comparing the two methods. Results: On overall, the 95% reference ranges of PG-I, PG-II, and PGR measured by CLIA were 23.00– 110.64 ng/mL, 2.50– 19.13 ng/mL, and 3.87– 13.30, respectively. Meanwhile, the reference ranges of PG-I, PG-II, and PGR measured by ELISA were 36.93– 205.06 ng/mL, 1.65– 17.96 ng/mL, and 7.50– 33.60, respectively. Both PG-I and PG-II levels measured by the two platforms were found to be influenced by sex and age. PGR measured by CLIA was influenced by age but not by sex, while PGR measured by ELISA was not affected by either age or sex. Regional factors did not significantly impact the PG results, except for PG-I detected by ELISA. Ultimately, reference ranges for PGs were established based on age and sex stratification. Additionally, the Spearman correlation analysis revealed that the correlation coefficients for PG-I, PG-II, and PGR detected by the two methods were 0.899, 0.887, and 0.777, respectively, indicating a strong correlation between the two methods. The regression equation for the PG levels detected by two methods was obtained through linear regression analysis. The ATE analysis provided a visual depiction of the consistency between the two methods, clearly indicating the poor agreement between them. Conclusion: This study established the reference ranges of PGs by strict and intact enrollment standard. In addition, the results indicated a strong linear relationship between the two methods, yet with a clear bias, which was valuable for laboratory interpretation. [ABSTRACT FROM AUTHOR]

The effect of spraying power on the microstructure and wear resistance of Ni-10 wt. %Al coating plasma sprayed with a 500 Hz sound vibration has been investigated. With the application of sound vibration, the compactness, cohesive bonding strength, and wear resistance of the coatings are all much higher. Meanwhile, with the increase of spraying power, the enhancement degree of the compactness, cohesive bonding strength, and wear resistance of the coatings are all increased. The sound vibration effects, which contain sound pressure, acoustic streaming, and heat effect, on the molten droplets are increased for their increasing melting induced by increasing spraying power. The wetting, flowing, and solidification of the molten droplets are all affected. Better wetting and flowing of the molten droplets promote their bonding on the surface of substrates and the solidified molten droplets, and their filling in the gaps of the solidified droplets. [ABSTRACT FROM AUTHOR]

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare autosomal recessive multisystem disorder that often presents with gastrointestinal and neurological symptoms. Here we report a 33‐year‐old male who presented with a 16‐year history of diarrhea with black stool and progressive weight loss. He complained of progressive bilateral blurred vision, upper eyelids heaviness, ocular motility impairment, and color blindness. Peripheral neuropathy, bilateral sensorineural deafness, hyperlactatemia, diabetes mellitus, hepatic steatosis, blood coagulation dysfunction, and diffuse leukoencephalopathy were detected in the systemic evaluation. Based on the novel homozygous pathogenic variant in the TYMP gene (c.1159+1G>A), he was diagnosed with MNGIE. On ophthalmic examinations, the thickness of the inner retina and ganglion cell complex significantly decreased. ERG showed diffusely decreased amplitudes. The electronegative electroretinogram, which was first reported in MNGIE, indicated a more severe inner retina impairment. The bilateral papillomacular bundle defect and central vision loss in MNGIE are consistent with classical mitochondrial optic neuropathies' features. According to the literature, pigmentary retinopathy, optic neuropathy, and abnormal pupillary reflexes are uncommon ocular features of MNGIE. This study contributes to a better understanding of ocular manifestations in MNGIE and demonstrates that MNGIE may have dyschromatopsia and an electronegative electroretinogram. [ABSTRACT FROM AUTHOR]