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The lateral free vibration of micro-rods initially subjected to axial loads based on a nonlocal continuum theory is considered. The effects of nonlocal long-range interaction fields on the natural frequencies and vibration modes are examined. A simply supported micro-rod is taken as an example; the linear vibration responses are observed by two different methods, including the separation of variables and multiple scales analysis. The relations between the vibration mode and dimensionless coordinate and the relations between natural frequencies and nonlocal parameters are analyzed and discussed in detail. The numerical comparison shows that the theoretical results by two different approaches have a good agreement, which validates the present micro-rod model that can be used as a component of the micro-electromechanical system.

Recurrent laryngeal nerve (RLN) injury is one of the most frequent postoperative complications of esophageal squamous cell carcinoma (ESCC) radical resection. This study aims to develop a novel scoring system to predict recurrent laryngeal nerve lymph node (RLNLN) metastases in early ESCC and explore the indications for precise RLN lymphadenectomy.Early stage ESCC patients from 2006 to 2014 were analyzed. Patient and pathologic characteristics were compared between patients with RLNLN metastases and those without. Univariate and multivariate analyses were performed to establish a scoring system that estimates the risks of RLNLN metastases. The indications for RLNLN dissection were validated by survival rate, postoperative complications, and metastases rate.A total of 311 cases selected from 1,466 ESCC patients were divided into the dissection group and the control group. Age, tumor length, macroscopic tumor type, T stage, tumor location and tumor differentiation were independent predictors of RLNLN metastases. The weighted scoring system included age (+2 for56 years), tumor length (+2 for over 4.45 cm), tumor location (+4 for upper thoracic, +2 for mid-thoracic) and macroscopic tumor type (+1 for advanced type). The total number of points estimated the probability of RLNLN metastases [low-risk (0-2 point), 0%; moderate-risk (3-4 points), 9.8%; and high-risk (4 points), 43.4%]. Besides, the dissection group had more complications and similar survival rate when compared with the control group.We developed a novel scoring system that accurately estimated the risk of RLNLN metastases in early ESCC patients. RLN lymphadenectomy may be safely omitted for the patients in the low-risk subgroup.