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BACKGROUND: The prognostic value of quantitative assessments of the number of retrieved lymph nodes (RLNs) in gastric cancer (GC) patients needs further study. AIM: To discuss how to obtain a more accurate count of metastatic lymph nodes (MLNs) based on RLNs in different pT stages and then to evaluate patient prognosis. METHODS: This study retrospectively analyzed patients who underwent GC radical surgery and D2/D2+ LN dissection at the Cancer Hospital of Harbin Medical University from January 2011 to May 2017. Locally weighted smoothing was used to analyze the relationship between RLNs and the number of MLNs. Restricted cubic splines were used to analyze the relationship between RLNs and hazard ratios (HRs), and X-tile was used to determine the optimal cutoff value for RLNs. Patient survival was analyzed with the Kaplan-Meier method and log-rank test. Finally, HRs and 95% confidence intervals were calculated using Cox proportional hazards models to analyze independent risk factors associated with patient outcomes. RESULTS: A total of 4968 patients were included in the training cohort, and 11154 patients were included in the validation cohort. The smooth curve showed that the number of MLNs increased with an increasing number of RLNs, and a nonlinear relationship between RLNs and HRs was observed. X-tile analysis showed that the optimal number of RLNs for pT1-pT4 stage GC patients was 26, 31, 39, and 45, respectively. A greater number of RLNs can reduce the risk of death in patients with pT1, pT2, and pT4 stage cancers but may not reduce the risk of death in patients with pT3 stage cancer. Multivariate analysis showed that RLNs were an independent risk factor associated with the prognosis of patients with pT1-pT4 stage cancer (P = 0.044, P = 0.037, P = 0.003, P < 0.001). CONCLUSION: A greater number of RLNs may not benefit the survival of patients with pT3 stage disease but can benefit the survival of patients with pT1, pT2, and pT4 stage disease. For the pT1, pT2, and pT4 stages, it is recommended to retrieve 26, 31 and 45 LNs, respectively.
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Purpose: Chronic post-surgical pain (CPSP) is one of the adverse outcomes after surgery, especially in thoracotomy. However, the prevalence of CPSP in elderly adults (≥65 years), is still limited. Therefore, the present study was undertaken to establish and validate the prediction model of CPSP in those patients after thoracic surgery, including thoracotomy and video-assisted thoracoscopic surgery. Patients and Methods: This retrospective, observational single-center cohort study was conducted in Nanfang Hospital, Southern Medical University, which randomly and consecutively collected 577 elderly patients who underwent thoracic surgery between January 1, 2017, and December 31, 2020. According to the Akaike information criterion, the prediction model was built based on all the data and was validated by calibration with 500 bootstrap samples. Results: The mean age of participants was 69.09±3.80 years old, and 63.1% were male. The prevalence of CPSP was 26.9%. Age more than 75 years, BMI, blood loss, longer length of hospital stays, and higher pre-operative neutrophil count were associated with CPSP. Except for these factors, we incorporated history of drinking to build up the prediction model. The areas under the curve (AUCs) of the prediction models were 0.66 (95% CI, 0.61-0.71) and 0.64 (95% CI, 0.59-0.69) in the observational and validation cohorts, respectively. And the calibration curve of the predictive model showed a good fit between the predicted risk of CPSP and observed outcomes in elderly patients. Conclusion: The present developed model may help clinicians to find high-risk elderly patients with CPSP after thoracic surgery and take corresponding measures in advance to reduce the incidence of CPSP and improve their life quality.
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The rapid development of flexible and wearable electronics has proposed a trend towards miniaturization, mobility, versatility and artificial intelligence. Triboelectric nanogenerators (TENGs) can make use of micro/nano multi-functional materials to harvest and store energy from the surrounding environment efficiently, which can drive smart portable electronics operating continuously and steadily. The increase in the output power density of the triboelectric nanogenerator requires new designs. In this work, a new grating TENG was proposed, and the two friction layers were fabricated by near-field electrospinning and conventional electrospinning with two parallel electrodes as a collector, respectively. The basic model of the simulation was simplified according to the highly ordered structure and the repeatability of the TENG grating structure. The effect of the effective contact area on the output of the TENG was further proved by fitting the calculation regularity of the two models with the experimental results. At the same time, the effect of the redundant electrode on the output of the TENG was verified by experiments. We found that this nanogenerator can achieve a very high output of 1800 W m-2 due to a more refined grating structure combined with modification of the contact area. The TENG can also be used as a selfpowered sensor to detect mechanical signals, which requires no additional power source to drive it. Meanwhile, the anisotropic nature of the TENG can also be utilized to sense angles, lock devices or encrypt information. This output control technology provides a more effective idea for future output power improvement, that is, a new generation of high-output TENGs can be designed by effectively adjusting the corresponding contact area and electrode area.
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With the development of technology, environmental problems have become more and more acute and the use of electronic devices in harsh environments has gradually attracted attention. For example, the friction layer of triboelectric nanogenerators (TENGs) may be contaminated and corroded in harsh environments (such as acidic, alkaline or oily environments), resulting in damage or destruction of the TENGs. In this study, we use electrospinning followed by a sintering process to prepare a super-hydrophobic sintered polyvinyl alcohol-polytetrafluoroethylene (S-PVA-PTFE) composite membrane and general industrial oil-absorbing paper to construct a TENG. The maximum power density of the TENG is 261 mW m-2, it can light up 100 blue LEDs, and can power a variety of small electronic devices. Moreover, after 72 h of soaking the friction layer in a strong acid solution followed by a strong alkali solution, the performance of the TENG has no obvious change. The TENG can work stably in an oily working environment. The TENG provides a novel approach for self-powered sensors that work in harsh environments.
