眼位对观察综合显示头盔信息的影响

目的 研究中心眼位和上调眼位时受试者对观察综合显示头盔信息的影响,测定两种眼位下头盔的位移与观察信息的关系,为综合显示头盔设计和使用提供依据. 方法 受试者为6名青年男性健康志愿者,视力良好.受试者佩戴综合显示头盔,头盔显示器为右眼单目,视场20°.中心眼位时,水平视线通过出瞳中心.上调眼位时,出瞳中心调整到水平视线上5°.通过分别施加与2.5Gz～8.0Gz的载荷相对应重量的沙袋模拟静载荷,保持10 s,重复3次；由低到高逐次加载.在AMST-HC-4E型载人离心机上,依次进行G值增长率为3 G/s,峰值分别为3.5Gz～8.0Gz持续10s的离心机试验.由受试者报告观察到的显示信息变化.通过三维坐标测量仪测量头盔位移. 结果 静加载时,上调眼位的头盔平均位移约为中心眼位的50％,信息丢失仅在视场上、下端小于2.5°的范围.离心机试验,上调眼位的头盔在6.5Gz10 s时整个视场信息基本可见,但中心眼位的头盔在6.0Gz10s时50％以上的信息丢失.静加载试验和离心机试验,上调眼位观察信息的变化趋势是一致的. 结论 上调眼位明显好于中心眼位对信息的观察.上调眼位对观察综合显示头盔信息的优势,为综合显示头盔的设计和使用提供了一条新途径.     

离心机模拟连续推拉动作训练方法研究

目的建立贴近实战化训练模式的连续推拉动作(PPM)离心机训练方法。方法调研提炼飞行训练中典型的PPM载荷参数,编制离心机模拟连续PPM曲线。16名战斗机飞行员作为志愿者,A组6名,采用-1Gz/3s→+6Gz/10s→2Gz/10s→0Gz/3s→+4.5Gz/10s→2Gz/10s→0.5Gz/3s→+5 Gz/10s连续PPM曲线,B组10名,采用-1Gz/3s→+6Gz/10s→2Gz/10s→0Gz/3s→+4.5Gz/10s→2Gz/10s→-1Gz/3s→+7Gz/5s连续PPM曲线(根据A组建议对曲线进行了改进),进行了HP动作对抗连续PPM离心机训练。志愿者在相对-Gz(小于+1Gz)暴露时采用HP动作的呼吸方式,在向+Gz转换时开始做较用力的HP动作,记录分析+Gz耐力、心率(HR)等指标的变化。结果A组6名志愿者均完成了连续PPM离心机训练,对PPM曲线提出了改进建议。B组9名志愿者采用改进的连续PPM曲线完成离心机训练。两组在相对-Gz时的HR均显著高于安静状态(P<0.05),连续PPM暴露时的HR变化趋势说明心血管调节有持续效应,其适应负荷有滞后。结论建立了高性能战斗机飞行员连续PPM离心机训练方法,模拟连续PPM曲线中不同水平-Gz与+Gz交替作用的模式更能体现实战化训练中长时间反复空战的特点,将应用于后续飞行员离心机训练。     

歼击机飞行员＋Gz暴露时座椅靠背面上体压分布变化

目的 建立载人离心机上记录和分析＋Gz暴露时体压分布的试验方法,探讨＋Gz引起的飞行员背部不适的原因及其防护措施,为进行＋Gz暴露时座椅靠背舒适性、腰背部防护措施有效性等研究提供参考. 方法 9名男性歼击机飞行员完成了＋3.0Gz持续10 s、＋5.0 Gz持续10 s及＋8.0Gz持续10s的载人离心机训练.用Teckscan压力分布测量系统记录并分析训练过程中座椅靠背面上的体压分布数据,包括接触面积、接触压力及峰值接触压力. 结果 接触面积、接触压力、峰值接触压力随着载荷的升高而增加,差异有统计学意义（F=181.40～2 848.43,P＜0.01）.＋5.0Gz时下背部的接触面积明显大于上背部（t=2.706,P＜0.05）;不同载荷暴露时,下背部的接触压力均大于上背部（t=4.370～8.169,P＜0.01）;＋1.0、＋3.0及＋5.0Gz暴露时下背部的的峰值接触压力显著大于上背部（t=2.455～8.087,P＜0.05）. 结论 本试验建立了动态观察和分析＋Gz暴露时靠背体压分布变化的试验方法.＋Gz暴露时座椅靠背面的体压分布变化提示高过载和抗荷动作对背部施加的作用力,可能是导致歼击机飞行员背部疾患的原因之一.     

高性能载人离心机推拉效应模拟方法研究

目的开发利用高性能载人离心机的功能,进行推拉效应(PPE)模拟方法的研究。方法推拉动作(PPM)加速度曲线的参数设为:Gmin为-1Gz持续5s,Gmax范围为从+2.5Gz持续10s开始按0.25Gz的幅度递增,对编制的模拟PPM加速度曲线进行试运行后,以12名战斗机飞行员和6名志愿者为受试者,分别测定了在预先有和无-1Gz5s作用情况下受试者的基础+Gz耐力。结果 -1Gz的产生会附带产生+1Gx和+0.5Gy,能够为人体所耐受。预先暴露于-1Gz5s后所有受试者的基础+Gz耐力均显著下降,志愿者组平均下降(0.87±0.13)G(P0.01),飞行员组平均下降(0.95±0.25)G(P0.01)。1名志愿者和1名飞行员受试者在PPM暴露的"拉"阶段发生加速度导致的意识丧失(G-LOC)结论在高性能载人离心机上初步建立推拉效应模拟方法,为后续的推拉效应研究奠定基础。     

＋Gz暴露对飞行员肾功能尿液检测指标的影响（摘要）

目的观察中等水平＋Gz暴露对飞行员尿微量白蛋白（microalbumin,MA）、尿α1微球蛋白（a1microglobulin,α1M）及尿常规十项检测指标的影响。方法33名歼击机飞行员接受离心机基础＋Gz耐力检查,最高加速度暴露水平为＋4．25G／10s,观察了10名飞行员＋Gz暴露后2h和23名飞行员＋Gz暴露后次日清晨上述尿液指标的变化情况。结果离心机检查前,     

持续性+Gz作用下头盔位移的测量分析

目的 测定飞行头盔在持续性＋Gz加速度作用下的位移,为飞行头盔的设计改进使用提供依据. 方法 通过离心机试验,获得不同＋Gz作用下志愿受试者佩戴飞行头盔和装显示器飞行头盔的录像资料,对录像资料进行图像分析,获得头盔的位移曲线. 结果 建立了利用录像资料定量分析头盔位移的方法,获得了不同＋Gz作用下头盔的位移. 结论 利用录像资料定量分析头盔位移的方法可行,测量结果为飞行头盔的设计改进使用提供了依据.     

中等水平+Gz暴露对飞行员尿微量白蛋白、尿α1微球蛋白及尿常规检测指标的影响

目的 观察中等水平+Gz暴露对飞行员尿微量白蛋白(MA)、尿α1微球蛋白(α1M)及尿常规10项检测指标的影响.方法 33名歼击机飞行员接受离心机基础+Gz耐力检查,最高加速度暴露水平为+4.25 G/10 s,观察10名飞行员+Gz暴露后2 h和23名飞行员+Gz暴露后24 h尿液指标中MA、α1M和尿常规10项指标的变化情况.结果 离心机检查前,33名飞行员尿液指标检测结果均正常.离心机检查完毕所有飞行员均无明显不适主诉.离心机检查后2 h有1名飞行员尿MA高于正常值,1名飞行员尿α1M高于正常值,次日复查正常,尿常规10项检测结果均正常,但+Gz暴露后2 h尿比重略有减小(t=4.129,P＜0.01),pH值略有增加(t=6.530,P＜0.01).离心机检查后24 h,有1名飞行员尿MA升高,1名飞行员尿α1M升高,1名飞行员尿常规10项检测检出少量红细胞,+Gz暴露后24 h尿比重及pH值与暴露前比较差异不显著.与离心机检查前比较,检查后2 h、24 h尿MA和口lM均无明显差异(t=1.616、0.376、0.640、0.422,P＞0.05).结论 中等水平+Gz暴露对少部分飞行员肾功能指标有轻微影响,个别人员可出现短暂异常,应注意加强+Gz暴露后飞行员肾功能的监测和保护.     

HP动作对抗推拉效应的离心机训练方法

目的 建立飞行员做HP动作对抗推拉效应(push-pull effect,PPE)的离心机训练方法. 方法 依据实际空战机动飞行中记录的推拉动作(push-pull maneuver,PPM)飞行参数,在载人离心机常规训练的基础上增加HP动作对抗PPE训练.受试者为6名飞行员.训练分3日进行,第1日采用预编程模式,飞行员穿抗荷服训练HP动作,载荷为+Gz增长率和下降率均为3 G/s、峰值分别为3、5、6、7G各持续10 s的曲线.第2日采用预编程模式,载荷为一组-1Gz持续5 s与+Gz分别为3、5、6、7G各持续10 s,G值增长率为2 G/s,下降率为1 G/s的PPM曲线,飞行员在-1Gz时采用HP动作的呼吸方式呼吸,从-1Gz向+Gz开始转换时即做较用力的HP动作,并随着+Gz的增加逐渐加大用力程度.第3日采用闭环模式,进行+3、+5、+8 Gz各持续10 s的HP与PHP动作训练.记录飞行员的+Gz耐力、心率(heart rate,HR)、呼吸率(breathing rate,BR)、双腿蹬力(muscular force of legs,F1egs)等指标的变化,并采用SPSS 10.0统计软件对数据进行自身对照t检验或重复测量的方差分析. 结果 第1日,6名飞行员采用HP动作,均完成了+7 Gz持续10 s离心机训练,其中1名飞行员因曾患椎间盘突出,退出后续训练.第2日,5名飞行员均完成了HP动作对抗PPE训练,通过了-1Gz持续5 s,至+3、+5、+6、+7 Gz持续10s的PPM训练.第3日,5名飞行员均完成了HP与PHP动作+8 Gz持续10 s训练.随+Gz值的增加,Flegs明显高于前一次+Gz暴露时(F=127.047～322.488,P＜0.01),HR、BR均显著高于+1 Gz安静时(P＜0.01).各+Gz暴露时的Flegs、HR、BR在3个训练日之间无显著差异;-1Gz暴露时的HR、BR均显著高于+1 Gz安静时(P＜0.01).飞行员主诉HP动作对抗PPE的离心机训练明显提高了对抗PPE的能力和信心. 结论 采用本研究建立的HP动作对抗PPE的离心机训练方法,能够显著提高飞行员对抗PPE的能力.     

+Gz 重复暴露对大鼠血小板粘附、聚集和血流变的影响

目的 探讨＋Gz重复暴露后，大鼠血小板计数（PLT）、粘附试验（PAdT)、聚集试验（PAgT)和血液流变学的变化。方法 利用动物离心机，将大鼠分别重复暴露＋10Gz 20s、＋10Gz 40s，共作用4次，两次之间间歇5min。观察＋Gz暴露后，PLT、PAdT、PAgT和血液流变学的变化。结果 ＋10Gz 40s组与对照组相比，PLT、PAdT和PAgT都明显增加（P＜0．05或P＜0．01）；全血粘度（ηb)、全血还原粘度（ηrd)和红细胞聚集指数（EAI）亦增加，差异均有显著性意义（P＜0．05）。＋10Gz 20s与对照组相比，各参数无明显变化。结论 ＋10Gz 40s重复暴露可引起血小板粘附、聚集功能增强和血液流变学的改变，而20s的10Gz暴露则不引起这些变化。     

离心机模拟复杂空战动作多轴向加速度耐力训练方法研究

目的建立贴近实战化训练模式的模拟复杂空战机动(ACM)离心机训练方法。方法调研提炼飞行训练中典型的载荷参数,编制模拟复杂ACM离心机加速度曲线, 7 G曲线为+4.5 Gz 10 s→+2 Gz5 s→+7 Gz 10 s→+3 Gz 5 s→-1 Gz 5 s→+4 Gz 5 s→+3 Gz 10 s→-2 Gy/+5 Gz 5 s,8 G曲线为+4.5 Gz 10 s→+2 Gz 5 s→+8 Gz 10 s→+3 Gz 5 s→-0.5 Gz 5 s→+4.5 Gz 5 s→+3 Gz 10 s→-2 Gy/+6 Gz 5 s,9 G曲线为+4.5 Gz 10 s→+2 Gz 5 s→+9 Gz 10 s→+3 Gz 5 s→0 Gz 5 s→+5 Gz5 s→+3 Gz 10 s→-2 Gy/+7 Gz 5 s。受试者为12名健康男性,结合HP动作呼吸方式进行了持续12周的针对腿部、腹部、腰部和颈部肌肉的力量训练。12名受试者采用7 G曲线,在力量训练前和力量训练后进行了离心机训练;力量训练后,10名受试者采用8 G曲线、9名受试者采用9 G曲线,进行了离心机训练,记录分析复杂加速度耐力、疲劳评分等指标的变化。结果力量训练前10名受试者完成了7 G曲线,力量训练后12名均完成了7 G曲线,且疲劳评分显著低于体能训练前(P0.01);9名受试者完成了8 G曲线;7名受试者完成了9 G曲线;训练时的呼吸疲劳评分9 G与8 G曲线分别显著高于8 G与7 G曲线(P0.05),腿部疲劳评分没有显著差异。结论建立了离心机模拟复杂ACM训练方法,ACM曲线包含有侧向加速度及推拉动作,兼顾最高载荷并高低搭配,有利于提高飞行员进行长时间复杂空战的能力,具有较高的实际应用价值。     

Head impact in a snowboarding accident

To effectively prevent sport traumatic brain injury (TBI), means of protection need to be designed and tested in relation to the reality of head impact. This study quantifies head impacts during a typical snowboarding accident to evaluate helmet standards. A snowboarder numerical model was proposed, validated against experimental data, and used to quantify the influence of accident conditions (speed, snow stiffness, morphology, and position) on head impacts (locations, velocities, and accelerations) and injury risk during snowboarding backward falls. Three hundred twenty‐four scenarios were simulated: 70% presented a high risk of mild TBI (head peak acceleration >80 g) and 15% presented a high risk of severe TBI (head injury criterion >1000). Snow stiffness, speed, and snowboarder morphology were the main factors influencing head impact metrics. Mean normal head impact speed (28 ± 6 km/h) was higher than equivalent impact speed used in American standard helmet test (ASTM F2040), and mean tangential impact speed, not included in standard tests, was 13.8 (±7 km/h). In 97% of simulated impacts, the peak head acceleration was below 300 g, which is the pass/fail criteria used in standard tests. Results suggest that initial speed, impacted surface, and pass/fail criteria used in helmet standard performance tests do not fully reflect magnitude and variability of snowboarding backward‐fall impacts.     

Video analysis of falls experienced by paediatric iceskaters and roller/inline skaters

Objectives

To evaluate differences in the way iceskaters and roller/inline skaters fall.

Methods

Children''s falls related to skating were videotaped and categorised based on type of skating activity, child''s estimated age, direction of fall, whether the child attempted to break the fall, and whether the head struck the skating surface.

Results

In total, 216 iceskating and 201 roller/inline skating falls were captured on videotape. In both iceskating and roller/inline skating, the majority of falls were forward in direction. The skaters attempted to break the falls with their arms or hands in over 90% of falls in both iceskating (93.1%) and roller/inline skating (94.5%). A greater proportion of falls in iceskating resulted in the head striking the skating surface (13.0%) than did those in roller/inline skating (3.0%) (odds ratio = 4.8; 95% confidence interval 1.9 to 13.3; p<0.001).

Conclusions

This study found that paediatric iceskaters and roller/inline skaters fall similarly and that both types of skaters try to break their falls with their arms or hands; however, because iceskating takes place on a low friction surface, attempts to break falls with the arms or hands are often unsuccessful, leading to head and face injuries. The development of a new type of protective gear, a wrist guard with a non‐slip palm, should stop iceskaters from striking the head, protect against upper extremity fractures, and unlike a bulky helmet, should not discourage children from skating.     

飞行员头盔质量特性测量设备和方法

目的研制一套飞行员头盔质量特性测量设备,满足飞行员头盔加装显示器、夜视镜以及头盔上配挂供氧面罩时质量特性的精确测量,为飞行头盔的设计、使用、评价提供试验条件和方法。方法根据飞行头盔的功能拓展,采用标准头模和两面垂直的开放式框架,按照静力平衡的原理设计三支点平衡的头盔质量和重心测量平台,按照扭摆原理设计头盔转动惯量测量的磁悬浮扭摆装置;研究制订头盔质量、重心和转动惯量的测量方法。结果研制了一套飞行员头盔质量、重心和转动惯量测量系统,建立了用于头盔重心和转动惯量测量的坐标体系,测量系统精度高,量程大,操作简便。结论飞行员头盔质量、重心和转动惯量测量系统设计科学、构造合理、使用可靠,可满足常规飞行保护头盔、加装显示器和夜视镜的飞行头盔、配挂供氧面罩飞行头盔质量特性的精确测量。     

Proposed injury thresholds for concussion in equestrian sports

ObjectivesEquestrian helmets are designed to pass certification standards based on linear drop tests onto rigid steel surfaces. However, concussions in equestrian sports occur most commonly when a rider is thrown off a horse and obliquely impacts a compliant surface such as turf or sand. This paper seeks to elucidate the mechanics of such impacts and thereby propose corresponding thresholds for the occurrence of concussion that can improve equestrian helmet standards and designs.DesignThe present study examined the biomechanics of real-world equestrian accidents and developed thresholds for the occurrence of concussive injury.MethodsTwenty-five concussive and 25 non-concussive falls in equestrian sports were reconstructed using a combination of video analysis, computational and physical reconstruction methods. These represented male and female accidents from horse racing and the cross-country phase of eventing.ResultsThe resulting thresholds for concussion [59 g, 2700 rad/s², 28 rad/s, 0.24 (MPS), 6.6 kPa and 0.27 (CSMD₁₀) for 50% risk] were consistent with those reported in the literature and represent a unique combination of head kinematic thresholds compared to other sports. Current equestrian helmet standards commonly use a threshold of 250 g and a linear drop to a steel anvil resulting in less than 15 ms impacts. This investigation found that concussive equestrian accidents occurred from oblique impacts to turf or sand with lower magnitude and longer duration impacts (<130 g and >20 ms). This suggests that current equestrian helmet standards may not adequately represent real-world concussive impact conditions and, consequently, there is an urgent need to assess the protective capacity of equestrian helmets under real-world conditions.     

大脑精确计时增强枕-顶区alpha波

目的：头戴式设备虽能够提升作战效能,但会导致头盔质心偏移和颈部关节力矩增加,增加飞行员颈部损伤的风险。为了保障飞行员健康,有必要开展飞行员颈部损伤评估。方法：开展了穿戴头盔的颈部肌肉疲劳实验,获取胸锁乳突肌、斜方肌和头夹肌的sEMG。利用变分模态分解方法将sEMG分解为若干模态分量,提取模态分量的多尺度熵,并将其作为特征向量,利用Fisher判别进行颈部损伤分类。结果：头盔质量特性的变化会导致肌肉信号模态分量的多尺度熵和中心频率的变化,而这种变化可以作为颈部肌肉的疲劳损伤分类评价的依据。结论：利用变分模态分解后的模态分量的多尺度熵,能较为合理地进行颈部肌肉疲劳损伤分类,可为飞行员颈部损伤的评估提供一定的方法支持。     

Helmets,head injury and concussion in sport

Research on the mechanism of concussion in recent years has been focused on the mechanism of injury as well as strategies to minimize or reverse injury. Sports-related head injury research has led to the development of head protective gear that has evolved over the years. Headgears have been designed to protect athletes from skull fractures, subdural hemorrhages and concussions. Over the years, through experience of athletes and continued scientific research, improvements in helmet design have been made. Although these advances have decreased the number of catastrophic injuries throughout sports, the effects on concussions are promising, but largely unproven. In this review, we will discuss development of helmets and studies analyzing their level of protection for both concussion and head injury. This will help us understand what future developments are still needed to minimize the risk of concussion among athletes in various forms of sports.     

Are self‐reported risk‐taking behavior and helmet use associated with injury causes among skiers and snowboarders?

Over the last 10 years, ski helmet use has steadily increased worldwide. According to the “risk compensation theory,” however, studies found that up to one third of skiers and snowboarders self‐reported to engage in more risk taking when wearing a ski helmet. Therefore, to evaluate whether self‐reported risk taking and ski helmet use affect accident causes on ski slopes, more than 2000 injured skiers and snowboarders were interviewed during the 2011/2012 winter season about accident causes and potential intrinsic and extrinsic risk factors. Chi‐square tests revealed that ski helmet use did not significantly differ between self‐reported risky and cautious people (81% vs 83%). Multivariate regression analysis revealed younger age groups [odds ratios (ORs) 1.8–1.9, P < 005], male sex (OR 2.4, P < 0.001), Austrian nationality (2.2, P < 0.001), higher skill level (1.7, P < 0.001), and off‐slope skiing (OR 2.2, P = 0.060) to be predictive for a risky behavior on ski slopes. Neither the use of skis or snowboards nor accident causes were significantly associated with a riskier behavior on ski slopes. In conclusion, self‐reported risk‐taking behavior and ski helmet use seem not to be associated with accident causes leading to an injury among recreational skiers and snowboarders.     

The role of interventional radiology in trauma

Introduction Interventional Radiology has evolved into a specialty having enormous input into the care of the traumatized patient.In all hospitals,regardless of size,the Interventional Radiologist must consider their relationships with the trauma service in order to     

Diagnóstico ecográfico del neumotórax

The ultrasonographic diagnosis of pneumothorax is based on the analysis of artifacts. It is possible to confirm or rule out pneumothorax by combining the following signs: lung sliding, the A and B lines, and the lung point. One fundamental advantage of lung ultrasonography is its easy access in any critical situation, especially in patients in the intensive care unit. For this reason, chest ultrasonography can be used as an alternative to plain-film X-rays and computed tomography in critical patients and in patients with normal plain films in whom pneumothorax is strongly suspected, as well as to evaluate the extent of the pneumothorax and monitor its evolution.     

Carbohydrate Supplementation during Exercise: Does It Help? How Much is Too Much?

KEY POINTS· Carbohydrate intake during exercise can delay the onset of fatigue and improve performance of prolonged exercise as well as exercise of shorter duration and greater intensity (e.g., continuous exercise lasting about 1h and intermittent high-intensity exercise), but the mechanisms by which performance is improved are different.