Additional length model for the impedance end correction of microperforated panels.

An additional length model is usually used to describe the reactive part of the impedance end correction of microperforated panels, which is extended to describe the resistive part. The cross-sectional impedance is computed along the axis of one perforation cell with a circular hole. Except for the obvious jumps in the narrow regions at the inlet and outlet of the perforation, the impedance varies linearly along the axis following exactly that of the viscous wave in the circular hole. The additional length for the impedance end correction is obtained by extrapolating the linearly varying impedance inside the hole. Empirical models for the resistive and reactive additional lengths are obtained based on the thermoviscous acoustic simulation with 96 test cases. Within an error of about 10%, a unified additional length model is presented for both the resistive and reactive parts of the impedance end correction. Comparison with other existing models shows the accuracy of the proposed model.

Broadband low frequency sound absorption using a monostable acoustic metamaterial.

This Letter presents a monostable acoustic metamaterial that has the potential to implement broadband sound absorption in low frequencies. The proposed metamaterial is realized by placing a flexible panel with a magnetic proof mass in a symmetric magnetic field. A theoretical model of the metamaterial is established and experimentally validated. Predictions and measurements demonstrate that the sound absorption peak frequency significantly shifts downwards with the increasing magnetic field. The relative bandwidth of the metamaterial is also broadened with the increasing magnetic field due to its inverse proportionality to the absorption peak frequency.

Wedge resection before lobectomy for patients with T1N0M0 non-small cell lung cancer: a propensity score matching analysis.

Background: Whether wedge resection of a tumor before lobectomy (Wed + Lob) can improve the prognosis of non-small cell lung cancer (NSCLC) has yet to be determined comprehensively. This study aimed to compare the effects of Wed + Lob with those of direct lobectomy (Lob) on survival and tumor cell dissemination in patients with T1N0M0 NSCLC. Methods: A cohort of 813 patients with T1N0M0 NSCLC who underwent lobectomy at a single center in China was investigated. After propensity score matching, the overall survival (OS) and disease-free survival (DFS) of patients were estimated using Kaplan-Meier plots. Associations between surgical strategies and patient survival were computed as hazard ratios and 95% confidence intervals using Cox proportional hazards regression models. Changes in folate receptor-positive circulating tumor cells (FR+ CTCs) after lobectomy were analyzed in another cohort from our hospital. Results: A total of 401 Wed + Lob cases were matched with 255 Lob cases according to their propensity scores. Although no significant differences were found in OS, multivariate analysis showed that patients with T1N0M0 NSCLC in the Wed + Lob group had significantly improved DFS (HR =0.583; P=0.012) compared to those in the Lob group. After surgery, a decrease in FR+ CTCs was observed in 21 of 23 patients (91.3%) in the Wed + Lob group and in 16 of 23 patients (69.6%) in the Lob group [mean changes: 6.10 (±7.80) FU per 3 mL vs. 1.31 (±4.39) FU per 3 mL; P=0.014]. Conclusions: Wed + Lob may improve DFS and reduce tumor cell dissemination in patients with T1N0M0 NSCLC.

Response to the combination use of pazopanib with olaratumab in a patient with lung-metastatic embryonal rhabdomyosarcoma: a case report.

Embryonal rhabdomyosarcoma (ERMS) is associated with a low prevalence, poor prognosis, and limited treatment efficacy. Here, we report a case of a 21-year-old male whose disease relapsed in the thoracic cavity following traditional chemotherapy. The patient received eight sequential cycles of traditional chemotherapy using a combination of the cyclophosphamide + vincristine + doxorubicin hydrochloride liposome (CAV) and etoposide + ifosfamide (IE) regimens. The therapeutic effect of the combination regimen had been worked in short times. After a month, ERMS had relapsed in the whole lung after traditional chemotherapy. The treatment method was changed immediately and the patient received targeted therapy with a combination of pazopanib and olaratumab. The therapeutic effect of the combination regimen was evaluated for a complete response (CR). After two months, CT imaging revealed that most of the metastatic lesions in the lung had disappeared. This is the first case to report the use of pazopanib and olaratumab in relapsed ERMS with a curative effect resulting in a CR. Pazopanib is approved for advanced soft tissue sarcoma (STS) and renal cell cancer. Thus, combining pazopanib with targeted therapy may play an important role and provide a reference for the treatment of relapsed ERMS.

Early extubation in operating room after single-lung transplantation: a single institutional experience.

BACKGROUND: Early endotracheal extubation in operating room (E-OR) after lung transplantation is rarely reported worldwide. Herein, we aim to explore the feasibility and safety of E-OR after lung transplantation and demonstrate its potential benefits. METHODS: This study is a single-center retrospective database analysis of 18 patients. All lung transplantation patients with E-OR attempted between June 2018 and September 2019 were included retrospectively. Perioperative variables, including ischemia time, total blood loss, blood lactic acid, the partial pressure of oxygen, partial pressure of oxygen/fraction of inspiration oxygen ratio, time of semi-open pulmonary artery occlusion clamp, extubation rate, and complications after E-OR, were analyzed. Data were compared using non-parametric tests and expressed as the median or number (percentage). RESULTS: Clinical data of 18 patients with E-OR attempted were collected. Overall, 15/18 (83.33%) patients successfully underwent E-OR without reintubation. Reintubation occurred in 3/18 (16.67%) patients; one patient presented with decreased blood oxygen saturation and unconsciousness, while two patients developed hypoxemia and respiratory failure after E-OR. Extracorporeal membrane oxygenation (ECMO) was not used postoperatively. No grade 3 primary graft dysfunction was observed and all eighteen patients were alive 1 year after the transplant. No postoperative hemodialysis and tracheotomy occurred. The median length of stay in the intensive care unit (ICU) for E-OR patients was 120 hours, the median length of postoperative hospital stay was 19 days, and the median hospitalization cost was 35,577 USD. CONCLUSIONS: Early endotracheal extubation in operating room was feasible and did not delay postoperative recovery in these 18 lung transplantation recipients.

Early removal of chest tubes leads to better short-term outcome after video-assisted thoracoscopic surgery lung resection.

BACKGROUND: Currently, some studies have shown that early removal of a chest tube after video-assisted thoracoscopic surgery (VATS) lobectomy is safe and can shorten the length of hospital stay. The purpose of our study was to retrospectively analyze the association between early chest tube removal and hospital stay in patients who have undergone lobectomy. METHODS: This retrospective analysis included patients undergoing different types of lung resections including lobectomy and wedge resection. Consecutive patients who underwent VATS lobectomy or wedge resection (March 2018 to April 2019) for lung tumor were analyzed. Patients were divided into two groups according to the drainage time: those in whom the chest tube was removed within 48 hours and the traditional management group. RESULTS: All 931 patients were included. After propensity score matching (PSM). There are no statistically significant differences between the two groups. Compared with the traditional management group, the hospital stay in the early removal group was significantly shorter (5.05±2.27 vs. 7.17±3.03; P<0.001). Regarding complications, compared with the traditional management group, the rates of both lung infection and no complication in the early removal group were less (0.2% vs. 2.3%, 93.0% vs. 91.1%; P=0.005), and the necessity of re-operation was also less (0% vs. 1.2%; P<0.001). Regarding both pleural effusion and thoracentesis, a slight increase in the patient number was observed in the early removal group compared with the traditional management group (4.7% vs. 4.0%, 1.2% vs. 0.9%; P=0.005). CONCLUSIONS: Compared with the traditional management group, early removal of the chest tube after VATS lobectomy and wedge resection is safe and feasible, and could decrease morbidity and postoperative complications, importantly, resulting in a shorter hospital stay.

Glasses-free 3D versus 2D video-assisted thoracoscopic thymectomy: a single-center short-term comparative study.

BACKGROUND: Thymectomy is widely used to for the treatment of thymomas, thymic cysts, thymic adenocarcinomas, and other thymic diseases. The development of video-assisted thoracoscopic surgery (VATS) thymectomy by our team offers the advantages of a glasses-free 3D thoracoscopic system for pulmonary surgery. The aim of the present retrospective study was to compare the advantages and short-term outcomes of glasses-free 3D VATS vs. 2D VATS for the treatment of thymic diseases. METHODS: The medical records of patients who underwent traditional 2D and glasses-free 3D video-assisted thoracoscopic thymectomy at the First Affiliated Hospital of Guangzhou Medical University from May 2015 to December 2018 were retrospectively reviewed, while focusing on the collection, evaluation, and comparison of clinical data and perioperative manifestations. RESULTS: A total of 152 patients were included, of which 71 patients underwent glasses-free 3D VATS and 81 underwent 2D VATS. There were no significant differences in demographic characteristics and baseline variables between the two groups (P>0.05). The overall surgical duration was significantly shorter in the 3D group than the 2D group (105.08±4.08 vs. 119.93±4.81 min, respectively, P=0.022). Further intergroup comparisons revealed that the median estimated intraoperative blood loss volume (10 vs. 20 mL, respectively, P=0.038) was less, postoperative thoracic tube indwelling rate (43/71 vs. 64/81, respectively, P=0.013) was lower, and the median duration of postoperative hospitalization (3 vs. 4 days, respectively, P=0.034) was shorter in the 3D group than the 2D group. Although no patient had died, complications occurred in 5 (7.0%) patients in the 3D group and 9 (11.1%) in the 2D group (P=0.387). CONCLUSIONS: As compared with traditional 2D thoracoscopy, glasses-free 3D VATS thymectomy is both safe and effective, and can shorten the surgical duration, reduce blood loss, decrease the indwelling rate of thoracic tube, and shorten the postoperative length of hospitalization.

[Effects of climate change on potato growth in semi-arid region of Loess Plateau, China].

Based on the 1988-2008 located observation and 2007-2008 encrypted observation of potato growth and the 1957-2008 meteorological observation in semi-arid region of Loess Plateau, this paper studied the effects of climate change on the potato growth in this region. In 1957-2008, the annual precipitation in this region had a descending trend, with a linear fitting rate of the annual precipitation change curves being - 13.359 mm x (10 a)(-1), while the annual mean temperature displayed an ascending trend, with a linear fitting rate of the annual mean temperature change curves being 0.239 degrees C x (10 a)(-1). During potato growth period, the aridity index displayed a marked ascending trend, and the linear fitting rate of the aridity index change curves was 0.102 x (10 a)(-1). The growth rate of potato tuber became faster from the 96th day after sowing, reached the maximum on the 110th day, and turned slower from the 124th day. The interval from sowing to seedling emergence was shortened by 1-2 d x (10 a)(-1), and that from inflorescence formation to reaping and of whole growth period was lengthened by 9-10 d x (10 a) (-1). In the study region, climate warming shortened the vegetative growth stage, but lengthened the reproductive growth stage and whole growth period of potato.