Parametric Optimization for Quality of Electric Discharge Machined Profile by Using Multi-Shape Electrode.

The electrical discharge machining (EDM) process is one of the most efficient non-conventional precise material removal processes. It is a smart process used to intricately shape hard metals by creating spark erosion in electroconductive materials. Sparking occurs in the gap between the tool and workpiece. This erosion removes the material from the workpiece by melting and vaporizing the metal in the presence of dielectric fluid. In recent years, EDM has evolved widely on the basis of its electrical and non-electrical parameters. Recent research has sought to investigate the optimal machining parameters for EDM in order to make intricate shapes with greater accuracy and better finishes. Every method employed in the EDM process has intended to enhance the capability of machining performance by adopting better working conditions and developing techniques to machine new materials with more refinement. This new research aims to optimize EDM's electrical parameters on the basis of multi-shaped electrodes in order to obtain a good surface finish and high dimensional accuracy and to improve the post-machining hardness in order to improve the overall quality of the machined profile. The optimization of electrical parameters, i.e., spark voltage, current, pulse-on time and depth of cut, has been achieved by conducting the experimentation on die steel D2 with a specifically designed multi-shaped copper electrode. An experimental design is generated using a statistical tool, and actual machining is performed to observe the surface roughness, variations on the surface hardness and dimensional stability. A full factorial design of experiment (DOE) approach has been followed (as there are more than two process parameters) to prepare the samples via EDM. Regression analysis and analysis of variance (ANOVA) for the interpretation and optimization of results has been carried out using Minitab as a statistical tool. The validation of experimental findings with statistical ones confirms the significance of each operating parameter on the output parameters. Hence, the most optimized relationships were found and presented in the current study.

Optimal Colonoscopic Surveillance Interval After Normal Baseline Screening Colonoscopy.

The optimal colonoscopic surveillance interval in the Chinese population is unclear. The present study aimed to assess the optimal colonoscopic surveillance interval after normal baseline screening colonoscopy to avoid overuse or underuse of colonoscopy. This retrospective study included individuals with normal baseline colonoscopy who had undergone at least 2 follow-up colonoscopy examinations at the Digestive Endoscopy Center of our hospital between 2000 and 2013. The risk factors for adenoma and the optimal colonoscopic surveillance interval were assessed. A total of 1,005 individuals (419 men; mean age, 49.34 ± 13.29 years) were included in the study. Of these, 169 individuals had adenomas at colonoscopic surveillance (mean, 1.32 ± 0.79 procedures). The mean adenoma diameter was 0.54 ± 0.38 cm, and the mean number of adenomas was 1.76 ± 1.29. The mean adenoma surveillance interval was 4.76 ± 2.89 years. The risk factors for adenoma identification were age more than 50 years and male gender. The optimal colonoscopic surveillance interval was 4.76 years according to an adenoma detection rate of 5%. The optimal colonoscopic surveillance interval is around 5 years for individuals with normal baseline colonoscopy. Age more than 50 years and male gender are risk factors for adenoma identification.

Primary clear cell carcinoma of the trachea: A CARE-compliant case report.

RATIONALE: Primary clear cell carcinoma of the lung is a rare condition, and presentation as an endotracheal lesion is even more unusual. In this report, we present a patient with clear cell carcinoma occurring in the trachea, which obstructed the tracheal lumen and lead to the respiratory distress. PATIENT CONCERNS: A 60-year old female patient was admitted due to a 6-month history of dyspnea with worsening symptoms for 1 month. Chest CT scan revealed a smooth nodular shadow with homogeneous density on the wall of upper trachea. DIAGNOSIS: Bronchoscopy therapy and surgical removal of the tumor were performed. The histopathological diagnosis revealed clear cell carcinoma. INTERVENTION: Surgical removal of the clear cell carcinoma was performed. OUTCOMES: The patient recovered well after the surgery and is now being followed-up after hospital discharge. LESSONS: Bronchoscopy is an essential tool for diagnosis of tracheal clear cell carcinoma. Surgical removal should be performed if possible.

Accuracy of interleukin-27 assay for the diagnosis of tuberculous pleurisy: A PRISMA-compliant meta-analysis.

BACKGROUND: The concentration of interleukin-27 (IL-27) in pleural effusions was found to be increased in tuberculous pleurisy and several studies have investigated the diagnostic value of IL-27 for tuberculous pleural effusions (TPEs), but the results varied a lot. We conducted the present study to comprehensively evaluate the diagnostic value of IL-27 for TPE. METHODS: Primary diagnostic test studies of IL-27 for TPE was searched and identified from databases. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ration, diagnostic odds ratio, and receiver operating characteristic curves (SROCs) were computed or pooled to summarize the overall test performance. RESULTS: Nine studies with a total number of 1226 patients were identified in our research. The main pooled estimates were as follows: sensitivity 0.92 [95% confidence interval (CI), 0.90-0.95], specificity 0.90 (95% CI, 088-0.92), and area under the SROC 0.97. No evidence of publication bias was detected. CONCLUSION: Our research suggested the good diagnostic value of IL-27 for TPE and it could be used as a diagnostic biomarker.

Diagnostic accuracy of tumor necrosis factor-alpha assay for tuberculous pleurisy: A PRISMA-compliant meta-analysis.

BACKGROUND: The diagnosis of tuberculous pleurisy is difficult and traditional methods are not always helpful. Many studies have focused on the tumor necrosis factor-alpha (TNF-α) assay in pleural effusion for the diagnosis of tuberculous pleurisy, but the results remain controversial. This meta-analysis was conducted to determine the overall diagnostic accuracy of TNF-α. METHODS: Relevant studies were searched from PubMed, Embase, Web of Science, Chinese National Knowledge Infrastructure (CNKI), Wangfang, and Weipu. We pooled the published results and computed the accuracy measures, including sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR). Receiver operating characteristic curves (SROC) and the area under the curve (AUC) were used to summarize the overall test performance. RESULTS: Twelve studies with 1022 patients met the inclusion criteria. The pooled sensitivity and specificity were 0.85 (95%CI, 0.81-0.89) and 0.80 (95% CI, 0.77-0.83) respectively. The area under the SROC curve was 0.89. CONCLUSIONS: The results of meta-analysis suggested that the TNF-α assay plays a vital role in the diagnosis of tuberculous pleurisy, whereas other test results or clinical findings should be interpreted together with the TNF-α assay to improve the overall diagnostic accuracy.