The evacuation of crowds in a building has always emerged as a vital issue in many accidents. The geometrical structure of a room, especially the exit design has a great influence on crowd evacuation under emergency c...The evacuation of crowds in a building has always emerged as a vital issue in many accidents. The geometrical structure of a room, especially the exit design has a great influence on crowd evacuation under emergency conditions. In this paper, the effect of exit location of a room on crowd evacuation in an emergency is investigated with mice. Two different exits are set in a rectangular chamber. One is located in the middle of a wall(middle-exit) and the other is at the corner of the chamber(corner-exit). Arching and clogging are observed in the flow of mice. The result based on the escape trajectories of mice shows a dynamic balance in the arch near the exit wherever the exit is located. We demonstrate that the occupant position in the arch has an effect on the escape sequence of mice. At a low stimulation level, the narrow middle-exit is more effective in increasing the flow rate of mice than the narrow corner-exit. However, the opposite result appears when the exit becomes wider. At a high stimulation level, the effect of exit location on flow of mice tends to be weakened. The results suggest that the specific level of stimulation needs to be taken into account when optimizing the evacuation efficiency of a crowd through the geometrical structure of a room.展开更多
Dear Sir,I am Dr.Yan Zhang,from Zhongshan Ophthalmic Center,State Key Laboratory of Ophthalmology Sun Yat-sen University,Guangzhou,Guangdong Province,China.I write to present a report concerning that diffusion tensor ...Dear Sir,I am Dr.Yan Zhang,from Zhongshan Ophthalmic Center,State Key Laboratory of Ophthalmology Sun Yat-sen University,Guangzhou,Guangdong Province,China.I write to present a report concerning that diffusion tensor imaging has high sensitivity in discriminating idiopathic demyelinating optic neuritis.展开更多
Objective To investigate the changes of hipbone biomechanics after the resection of ischiopubic tumors and their relationships with the complications in the convalescent stage, and directing the postoperative pelvic r...Objective To investigate the changes of hipbone biomechanics after the resection of ischiopubic tumors and their relationships with the complications in the convalescent stage, and directing the postoperative pelvic reconstruction. Methods DICOM data were used to create an intact hipbone finite element model and postoperative model. The biomechanical indices on the same region in the two models under the same boundary condition were compared. The differences of displacement, stress, and strain of the two models were analyzed with statistical methods. Results The distribution areas of the hipbone nodes' displacement, stress, and strain were similar before and after the simulated operation. The sacroiliac joint nodes' displacement (P=0.040) and strain (P=0.000), and the acetabular roof nodes' stress (P=0.000) and strain (P=0.005) of two models had significant differences, respectively. But the sacroiliac joint nodes' stress (P=0.076) and the greater sciatic notch nodes' stress (P=0.825) and strain (P=0.506) did not have significant differences. Conclusions The resection of ischiopubic tumors mainly affect the biomechanical states of the homolateral sacroiliac joint and acetabular roof. The complications in the convalescent stage are due to the biomechanical changes of the sacroiliac joint and the acetabular roof and disappearances of the stabilization and connection functions of the pubic symphysis and superior ramus of pubis.展开更多
Objective:To explore the application value of neutrophil/lymphocyte ratio (NLR) combined with high sensitive C reactive protein (hs-CRP) in the evaluation of community acquired pneumonia (CAP). Methods:From November 2...Objective:To explore the application value of neutrophil/lymphocyte ratio (NLR) combined with high sensitive C reactive protein (hs-CRP) in the evaluation of community acquired pneumonia (CAP). Methods:From November 2015 to October 2016, 58 cases of CAP patients admitted in our department were selected as research objects and were divided into low risk group and high risk group according to the PSI score and CURB-65 standard for evaluation. They were divided into improved group (48 cases) and death group (10 cases) according to prognosis. Hs-CRP was determined by immunoturbidimetric assay, procalcitonin (PCT) by immunofluorescence, NLR by count method of laser scattering, and white blood (WBC) was counted. The differences in WBC, PCT, NLR and hs-CRP between different risk groups were compared, and the correlation was evaluated using Spearman's rank correlation analysis method. The changes in indexes were observed in the improved and death cases. Results:The high risk group had higher NLR, PCT and hs-CRP than low risk group (P<0.05), while no significant difference was found in WBC (P>0.05). No correlation was found between NLR and WBC, while a strong correlation was found between hs-CRP and PCT. The WBC, PCT, NLR and hs-CRP levels were significantly lower in the improved group than the death group (P<0.05). Conclusions:NLR combined with hs-CRP, WBC, and PCT has a good assessment of the severity of CAR, and high levels of NLR, hs-CRP, WBC, and PCT predict the severity of the disease and poor prognosis.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFB1200404)
文摘The evacuation of crowds in a building has always emerged as a vital issue in many accidents. The geometrical structure of a room, especially the exit design has a great influence on crowd evacuation under emergency conditions. In this paper, the effect of exit location of a room on crowd evacuation in an emergency is investigated with mice. Two different exits are set in a rectangular chamber. One is located in the middle of a wall(middle-exit) and the other is at the corner of the chamber(corner-exit). Arching and clogging are observed in the flow of mice. The result based on the escape trajectories of mice shows a dynamic balance in the arch near the exit wherever the exit is located. We demonstrate that the occupant position in the arch has an effect on the escape sequence of mice. At a low stimulation level, the narrow middle-exit is more effective in increasing the flow rate of mice than the narrow corner-exit. However, the opposite result appears when the exit becomes wider. At a high stimulation level, the effect of exit location on flow of mice tends to be weakened. The results suggest that the specific level of stimulation needs to be taken into account when optimizing the evacuation efficiency of a crowd through the geometrical structure of a room.
基金Supported by Natural Science Foundation of Guangdong Province(No.2015A030313076)Fundamental Research Funds of the State Key Laboratory of Ophthalmology
文摘Dear Sir,I am Dr.Yan Zhang,from Zhongshan Ophthalmic Center,State Key Laboratory of Ophthalmology Sun Yat-sen University,Guangzhou,Guangdong Province,China.I write to present a report concerning that diffusion tensor imaging has high sensitivity in discriminating idiopathic demyelinating optic neuritis.
基金Supported by Medical Scientific Research Foundation Item of Guangdong Province(A2008800)Science and Technology ProgramItem of Zhongshan City(20082A071and20113A049)
文摘Objective To investigate the changes of hipbone biomechanics after the resection of ischiopubic tumors and their relationships with the complications in the convalescent stage, and directing the postoperative pelvic reconstruction. Methods DICOM data were used to create an intact hipbone finite element model and postoperative model. The biomechanical indices on the same region in the two models under the same boundary condition were compared. The differences of displacement, stress, and strain of the two models were analyzed with statistical methods. Results The distribution areas of the hipbone nodes' displacement, stress, and strain were similar before and after the simulated operation. The sacroiliac joint nodes' displacement (P=0.040) and strain (P=0.000), and the acetabular roof nodes' stress (P=0.000) and strain (P=0.005) of two models had significant differences, respectively. But the sacroiliac joint nodes' stress (P=0.076) and the greater sciatic notch nodes' stress (P=0.825) and strain (P=0.506) did not have significant differences. Conclusions The resection of ischiopubic tumors mainly affect the biomechanical states of the homolateral sacroiliac joint and acetabular roof. The complications in the convalescent stage are due to the biomechanical changes of the sacroiliac joint and the acetabular roof and disappearances of the stabilization and connection functions of the pubic symphysis and superior ramus of pubis.
文摘Objective:To explore the application value of neutrophil/lymphocyte ratio (NLR) combined with high sensitive C reactive protein (hs-CRP) in the evaluation of community acquired pneumonia (CAP). Methods:From November 2015 to October 2016, 58 cases of CAP patients admitted in our department were selected as research objects and were divided into low risk group and high risk group according to the PSI score and CURB-65 standard for evaluation. They were divided into improved group (48 cases) and death group (10 cases) according to prognosis. Hs-CRP was determined by immunoturbidimetric assay, procalcitonin (PCT) by immunofluorescence, NLR by count method of laser scattering, and white blood (WBC) was counted. The differences in WBC, PCT, NLR and hs-CRP between different risk groups were compared, and the correlation was evaluated using Spearman's rank correlation analysis method. The changes in indexes were observed in the improved and death cases. Results:The high risk group had higher NLR, PCT and hs-CRP than low risk group (P<0.05), while no significant difference was found in WBC (P>0.05). No correlation was found between NLR and WBC, while a strong correlation was found between hs-CRP and PCT. The WBC, PCT, NLR and hs-CRP levels were significantly lower in the improved group than the death group (P<0.05). Conclusions:NLR combined with hs-CRP, WBC, and PCT has a good assessment of the severity of CAR, and high levels of NLR, hs-CRP, WBC, and PCT predict the severity of the disease and poor prognosis.
