A Micro-Topography Measurement and Compensation Method for the Key Component Surface Based on White-Light Interferometry.

The grinding grooves of material removal machining and the residues of a machining tool on the key component surface cause surface stress concentration. Thus, it is critical to carry out precise measurements on the key component surface to evaluate the stress concentration. Based on white-light interferometry (WLI), we studied the measurement distortion caused by the reflected light from the steep side of the grinding groove being unable to return to the optical system for imaging. A threshold value was set to eliminate the distorted measurement points, and the cubic spline algorithm was used to interpolate the eliminated points for compensation. The compensation result agrees well with the atomic force microscope (AFM) measurement result. However, for residues on the surface, a practical method was established to obtain a microscopic 3D micro-topography point cloud and a super-depth-of-field fusion image simultaneously. Afterward, the semantic segmentation network U-net was adopted to identify the residues in the super-depth-of-field fusion image and achieved a recognition accuracy of 91.06% for residual identification. Residual feature information, including height, position, and size, was obtained by integrating the information from point clouds and super-depth-of-field fusion images. This work can provide foundational data to study surface stress concentration.

Genomic Shift in Population Dynamics of mcr-1-positive Escherichia coli in Human Carriage.

Emergence of the colistin resistance gene, mcr-1, has attracted worldwide attention. Despite the prevalence of mcr-1-positive Escherichia coli (MCRPEC) strains in human carriage showing a significant decrease between 2016 and 2019, genetic differences in MCRPEC strains remain largely unknown. We therefore conducted a comparative genomic study on MCRPEC strains from fecal samples of healthy human subjects in 2016 and 2019. We identified three major differences in MCRPEC strains between these two time points. First, the insertion sequence ISApl1 was often deleted and the percentage of mcr-1-carrying IncI2 plasmids was increased in MCRPEC strains in 2019. Second, the antibiotic resistance genes (ARGs), aac(3)-IVa and blaCTX-M-1, emerged and coexisted with mcr-1 in 2019. Third, MCRPEC strains in 2019 contained more virulence genes, resulting in an increased proportion of extraintestinal pathogenic E. coli (ExPEC) strains (36.1%) in MCRPEC strains in 2019 compared to that in 2016 (10.5%), implying that these strains could occupy intestinal ecological niches by competing with other commensal bacteria. Our results suggest that despite the significant reduction in the prevalence of MCRPEC strains in humans from 2016 to 2019, MCRPEC exhibits increased resistance to other clinically important ARGs and contains more virulence genes, which may pose a potential public health threat.

Efficacy and Prognostic Factors of Combined Hyperbaric Oxygen Therapy in Patients With Idiopathic Sudden Sensorineural Hearing Loss.

Purpose Idiopathic sudden sensorineural hearing loss is a clinical emergency with an increased incidence of occurrence in recent years. Hyperbaric oxygen has been widely used in the clinical treatment of sudden hearing loss. However, prognostic factors related to its curative effects are still not clear, which hinders its clinical application. The aim of this study was to investigate the efficacy and prognostic factors of hyperbaric oxygen therapy (HBOT) plus drug therapies in the treatment of sudden hearing loss. Method Patients with sudden hearing loss who were treated with hyperbaric oxygen from April to October 2017 were retrospectively included. Clinical information was collected, including pure-tone audiometry data before and after hyperbaric oxygen treatment, age, gender, hearing curve classification, concomitant symptoms, history of diseases (diabetes and hypertension), history of hormone therapy, start time of hyperbaric oxygen treatment, and total number of hyperbaric oxygen treatments. The prognostic factors were analyzed with univariate and multivariate analyses. Results Sixty-four patients with sudden hearing loss were enrolled, including 7 cases of low-frequency loss, 4 cases of high-frequency loss, 32 cases of flat loss, and 21 cases of complete hearing loss. After HBOT, there were 16 cases (25%) of complete recovery, 15 cases (23.43%) of partial recovery, 7 cases (10.93%) of slight improvement, and 26 cases (40.63%) of no improvement. The total effective rate was 59.37%. Twelve of 21 cases (57.14%) of complete hearing loss showed recovery. Multivariate logistic regression analysis showed that the start time of HBOT ≤ 7 days from disease onset was independently associated with hearing recovery ( OR = 27.763, 95% CI [4.209, 183.115], p = .001). Conclusion Combined HBOT can improve the hearing impairment of sudden hearing loss. The early HBOT showed the most promising therapeutic effects, especially among patients with complete hearing loss.

Association of prepro-orexin polymorphism with obstructive sleep apnea/hypopnea syndrome.

BACKGROUND: Because of the potential role of orexin neuronal circuitry in the regulation of sleep and wakefulness and arousal and breathing, it seems reasonable to speculate that abnormalities in the prepro-orexin gene could be relevant to studies of obstructive sleep apnea/hypopnea syndrome (OSAHS); and it might be a candidate gene in the pathogenesis of OSAHS. OBJECTIVE: The present study investigated whether single nucleotide polymorphisms (SNPs) in the human prepro-orexin gene are associated with OSAHS in Han Chinese people. METHODS: A total of 394 subjects (217 cases and 177 control subjects) were recruited from China. Diagnostic polysomnography was performed in all patients and control subjects. SNPs in potentially functional regions of the gene were identified; and genotypes, determined by direct sequencing. RESULTS: By sequencing the promoter, 2 exons, and the exon-intron junctions of the prepro-orexin gene, the g11182C>T SNP was identified. Statistical analysis showed that there were significant differences in the genotype distribution between patients with OSAHS and the control group (χ(2)(2) = 6.437, P = .04). Variant allele T of the g1182C>T polymorphism was more commonly found in patients with OSAHS as compared with control subjects (χ(2)(1) = 5.648, P = .017; odds ratio, 1.449; 95% confidence interval, 1.0466-1.968). CONCLUSIONS: Our results suggest that the prepro-orexin gene polymorphism g1182C>T is associated with susceptibility to OSAHS in Han Chinese. This study provides insights into the genetic information for future studies regarding this gene in OSAHS.