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A double-laser-beam lidar was successfully developed in 2010 to measure the K layer over Yanqing County, Beijing (40.5°N, 116.2°E). Comprehensive statistical analyses of sporadic K (Ks) layer parameters were conducted using two years of lidar data, and the parameters of the Ks layers and their distribution obtained by the analyses are described. The seasonal distribution of Ks occurrence was obtained, with two maxima observed in January and July, respectively. The seasonal distributions of sporadic E (Es) occurrence over Beijing differ from those of Ks occurrence. However, good correlations between Es and Ks in case by case study were found. We also found that four Ks events with peak altitudes lower than 90 km were associated with large and sharp temperature increases in five comparative examples. [ABSTRACT FROM AUTHOR]

During the total solar eclipse on July 22, 2009 in Wuhan, the joint observation test of Na layer and ionosphere was conducted by using the daytime observation atmospheric lidar and the GPS ionosphere detector. The results show that the full width at half maximum (FWHM) of Na layer density slightly narrowed during the total solar eclipse and broadened after the eclipse, while the height of Na peak slightly decreased in the eclipse and increased after the eclipse. These implying that Na layer changes reflect the rapid process of sunrise and sunset. The ionosphere total electron content (TEC) and the sky background light noise also presented an obvious fluctuation characteristic with the changes of solar irradiation during the process of total solar eclipse. The difference lies in that the changes of FWHM of Na layer atoms are much slower than that of ionosphere, the reason for this might be that the Na layer, after being disturbed by the total solar eclipse, will generate a series of complicated photochemical reactions and momentum transport processes, and then recombine the Na atoms. The Na atoms to be detected by the lidar need a lag process, which rightly conforms to the theoretical simulated results. [ABSTRACT FROM AUTHOR]

The mechanical properties of the tissue engineering scaffold are important as they are tightly related the regeneration of structural tissue. The application of poly( l-lactic acid) (PLLA) nanofiber scaffolds in tissue engineering has been hindered by their insufficient mechanical properties. In the study, halloysite nanotubes (HNTs) were used to reinforce the mechanical properties of PLLA-based nanofibers. 4 wt% HNT/PLLA nanofiber membranes possess the best mechanical performance, which represents 61 % increase in tensile strength, 100 % improvement of Young's modulus, 49 % augment of elongation to break, as well as 181 % elevation in energy to break compared with neat PLLA samples. The satisfactory enhancement effect of HNTs can be attributed to the effective dispersion and incorporation of HNTs in PLLA matrix, which have been confirmed by the analysis of SEM, TEM, and FTIR. The addition of HNTs also improves the degree of crystallization and thermal stability of PLLA-based nanofibers. HNT-incorporated PLLA nanofiber membranes possess higher protein adsorption from fetal bovine serum than the neat PLLA specimen. Therefore, the introduction of HNTs can effectively enhance the mechanical properties of PLLA nanofiber scaffolds. HNT/PLLA nanofiber scaffolds possess potential application in skin tissue engineering. [ABSTRACT FROM AUTHOR]

Background: Video-assisted thoracoscopic surgery (VATS) is a new area of exploration and evolution in thoracic minimal invasive surgery. The uniportal VATS approach has become popular during lung resection for small nodules and ground glass lesions. Our objective is to investigate the efficacy, availability and safety of uniportal VATS anatomical segmentectomy compared with conventional VATS in patients for lung resection. Methods: Surgical patients of perioperative period who admitted and underwent uniportal, two-port and conventional three-port VATS segmentectomy were analyzed and compared retrospectively during the year 2017 to 2018. Results: During the research period, of 111 patients who had VATS anatomical segmentectomy, 38 underwent uniportal, 43 underwent two-port, and 30 underwent three-port VATS. Four patients underwent conversion to thoracotomy. There were no postoperative mortalities, and there were no significant differences among the three groups in surgical outcomes, including operative time, blood loss, conversions to thoracotomy, drainage time and volume, lymph node dissection, postoperative complications and hospital stay. The pain scores of visual analog scale (VAS) significantly decreased in uniportal group when operation is finished (P < 0.05). Conclusion: This study demonstrates that uniportal VATS anatomical segmentectomy is a quite safe surgical technology, as well as feasible, which can cause reduced postoperative pain and less surgical trauma compared to conventional VATS. More experiences and observations of large samples are on the way. [ABSTRACT FROM AUTHOR]

Background: Uniportal video-assisted thoracoscopic surgery (VATS) lobectomy has emerged as a promising and exciting approach for minimally invasive thoracic surgeries. However, nearly all reported uniportal VATS lobectomies are performed via an intercostal route, and chest wall trauma remains an issue. Here, we report the use of a novel uniportal VATS technique involving a subxiphoid route for pulmonary lobectomies. Methods: We retrospectively analyzed perioperative data for patients who underwent subxiphoid uniportal and traditional three-port VATS lobectomies from January 2016 to January 2017 at our hospital. Results: During the study period, 37 patients successively underwent subxiphoid uniportal VATS lobectomies, including three synchronous bilateral pulmonectomies; 68 patients underwent traditional three-port VATS. There were no surgical or 30-day postoperative mortalities, and no significant between-group differences were found in the number of retrieved lymph nodes, number of explored nodal stations, blood loss, drainage time, postoperative complications, or length of hospital stay. Operative time was longer in the subxiphoid uniportal VATS group than in the traditional three-port VATS group (P < 0.001). Visual analog scale (VAS) pain scores after surgery were significantly lower in the subxiphoid uniportal VATS group (P < 0.05). Conclusions: Subxiphoid uniportal VATS lobectomy is a safe and feasible surgical procedure associated with reduced surgical trauma and postoperative pain as well as improved cosmetic results compared with traditional VATS. Moreover, this procedure is better suited for patients receiving synchronous bilateral pulmonectomy. Further long-term follow-up analyses involving more patients are ongoing. Trial registry number: ClinicalTrials.gov NCT03051438. [ABSTRACT FROM AUTHOR]