BACKGROUND:Airway foreign bodies(AFBs)is an interdisciplinary area between emergency medicine,pediatrics and otolaryngology.It is a life-threatening condition that is not infrequently seen;however,it is poorly covered...BACKGROUND:Airway foreign bodies(AFBs)is an interdisciplinary area between emergency medicine,pediatrics and otolaryngology.It is a life-threatening condition that is not infrequently seen;however,it is poorly covered in medical literature.Accidental aspiration of an element into airways is a widespread clinical scenario among children under 3 years,predominantly males.Moreover,it is the leading cause of infantile deaths and the fourth one among preschool children.DATA RESOURCES:A systemic search was conducted in July 2015 using Pub Med/Pub Med Central Database of The National Center for Biotechnology Information(NCBI)(http://www.ncbi.nlm.nih.gov/).A total of 1 767 articles were identified and most of them were meta-analyses,systematic reviews,and case series.Those thoroughly discussing assessment and management of AFBs were retrieved.RESULTS:AFBs episodes may be either witnessed or missed.Presence of a witness for the inhalation is diagnostic.The later usually present with persistent active cough.A classical triad of paroxysmal cough,wheezing,and dyspnoea/decreased air entry was reported,though many presentations have inconsistent findings.Hence,diagnosis requires high index of clinical suspicion.Flexible fibro-optic bronchoscopy is the gold standard of diagnosis,whereas inhaled objects are best retrieved by rigid bronchoscopes.CONCLUSIONS:Close supervision of pediatrics is the hallmark of prevention.Caregivers should ensure a safe surrounding milieu,including the toys their offspring play with.Immediate complications result from direct obstruction or injury by the inhaled object.Alternatively,prolonged lodging traps air and induces inflammatory response causing atelectesis and pneumonia,respectively.展开更多
Based on 3D, steady N-S equations and k-e turbulence model, Fluent was employed to do numerical simulation for lateral aerodynamic performance of 6-axis X2K double-deck container trains with two different loading form...Based on 3D, steady N-S equations and k-e turbulence model, Fluent was employed to do numerical simulation for lateral aerodynamic performance of 6-axis X2K double-deck container trains with two different loading forms, and speed limits of the freight trains were studied. The result indicates that under wind environment： 1） As for vehicles without and with cross-loaded structure, aero-pressure on the former is bigger, but air velocity around the latter is larger; 2） When sideslip angle θ=0°, the airflow is symmetry about train vertical axis; when θ〉0°, the airflow is detached at the top of vehicles, and the air velocity increases above the separated line but decreases below it; 3） With θ increasing, the lateral force on the mid vehicle firstly increases but decreases as θ=75°; 4） When the 6-axis X2K fiat car loads empty boxes of a 40 ft and a 48 ft at 120 km/h, the overturning wind speed is 25.19 m/s, and the train should be stopped under the 12th grade wind speed.展开更多
文摘BACKGROUND:Airway foreign bodies(AFBs)is an interdisciplinary area between emergency medicine,pediatrics and otolaryngology.It is a life-threatening condition that is not infrequently seen;however,it is poorly covered in medical literature.Accidental aspiration of an element into airways is a widespread clinical scenario among children under 3 years,predominantly males.Moreover,it is the leading cause of infantile deaths and the fourth one among preschool children.DATA RESOURCES:A systemic search was conducted in July 2015 using Pub Med/Pub Med Central Database of The National Center for Biotechnology Information(NCBI)(http://www.ncbi.nlm.nih.gov/).A total of 1 767 articles were identified and most of them were meta-analyses,systematic reviews,and case series.Those thoroughly discussing assessment and management of AFBs were retrieved.RESULTS:AFBs episodes may be either witnessed or missed.Presence of a witness for the inhalation is diagnostic.The later usually present with persistent active cough.A classical triad of paroxysmal cough,wheezing,and dyspnoea/decreased air entry was reported,though many presentations have inconsistent findings.Hence,diagnosis requires high index of clinical suspicion.Flexible fibro-optic bronchoscopy is the gold standard of diagnosis,whereas inhaled objects are best retrieved by rigid bronchoscopes.CONCLUSIONS:Close supervision of pediatrics is the hallmark of prevention.Caregivers should ensure a safe surrounding milieu,including the toys their offspring play with.Immediate complications result from direct obstruction or injury by the inhaled object.Alternatively,prolonged lodging traps air and induces inflammatory response causing atelectesis and pneumonia,respectively.
基金Project supported by Scholarship Award for Excellent Doctoral Student granted by Ministry of Education,ChinaProject(2012QNZT029) supported by the Fundamental Research Funds for the Central Universities of China+1 种基金Project(CX2010B122) supported by Hunan Provincial Innovation Foundation for Postgraduate,ChinaProject(2010ybfz088) supported by the Foundation of Excellent Doctoral Dissertation of Central South University,China
文摘Based on 3D, steady N-S equations and k-e turbulence model, Fluent was employed to do numerical simulation for lateral aerodynamic performance of 6-axis X2K double-deck container trains with two different loading forms, and speed limits of the freight trains were studied. The result indicates that under wind environment： 1） As for vehicles without and with cross-loaded structure, aero-pressure on the former is bigger, but air velocity around the latter is larger; 2） When sideslip angle θ=0°, the airflow is symmetry about train vertical axis; when θ〉0°, the airflow is detached at the top of vehicles, and the air velocity increases above the separated line but decreases below it; 3） With θ increasing, the lateral force on the mid vehicle firstly increases but decreases as θ=75°; 4） When the 6-axis X2K fiat car loads empty boxes of a 40 ft and a 48 ft at 120 km/h, the overturning wind speed is 25.19 m/s, and the train should be stopped under the 12th grade wind speed.
