Head trauma can cause transient elevation of intraocular pressure in patients with open angle glaucoma

AIM: To describe a newly-recognized entity, illustrated by five cases of glaucoma in whom trauma to the head, but not the eye, resulted in marked, transient elevation of intraocular pressure (IOP). METHODS: Retrospective case series. Chart review. RESULTS: All five cases had a diagnosis of primary open-angle glaucoma prior to the experience of trauma to the head. All cases had an unusual elevation of IOP (around 70 percent) for days to weeks following the trauma, after which the IOP fell to pre-accident levels. No cause other than the trauma could be determined. CONCLUSION: The relationship between head trauma and elevation of IOP appears real.

Sensor fusion for heading angle estimation based on random forest algorithm

To improve the accuracy of the calculation of a heading angle under magnetic interference,magnetometers and inertial measurement units(IMUs)were fused.The observation value of the heading angle was deduced on the basis of the modeling of the magnetometer error and the analysis of the relation of the magnetometer triaxial output and the distribution characteristics of the magnetic field at two adjacent time periods.Meanwhile,the gyro state and angular velocity increment were used as the basis of the IMU to calculate the prediction value of the heading angle.With the changes in the heading angle and environmental interference,a random forest(RF)algorithm was used to iteratively calculate the weights to fuse the observation value of the heading angle based on the magnetometer and the prediction value of the heading angle based on the IMU.The results show that relative to the common sensor fusion method,the proposed sensor fusion method based on the RF algorithm achieved an approximate 60%improvement in heading angle accuracy.Hence,the proposed method can effectively improve the accuracy of the heading angle under magnetic interference by using an RF algorithm to calculate the output weights of the magnetometer and IMU.

成人骨性AngleⅢ类错颌下颌边缘运动的肌电变化研究

以肌电仪对３０名成人骨性ＡｎｇｌｅⅢ类错者的咀嚼肌肌电变化进行测量，并与正常成人比较，发现成人骨性ＡｎｇｌｅⅢ类错患者咀嚼肌有异常肌活动，肌电变化出现异常。其在下颌前伸运动时，颞肌前束出现异常肌活动，下颌后退运动时，其嚼肌出现异常肌活动，两者之肌电位均较正常者高。下颌左右侧方运动时，其同侧嚼肌和对侧颞肌前束均出现异常肌活动，肌电位亦较正常者高。

AngleⅡ^1治疗牙弓改变在模型和头颅侧位片的相关性

目的对AngleⅡ1错病例在矫治后头颅侧位片及模型的测量结果进行回顾性分析,了解在模型和头颅侧位片上牙弓变化的相关性。方法选择17～31岁AngleⅡ1错患者20例,对其治疗前后头颅侧位片和牙模型的19项指标进行可重复测量的方差分析。结果治疗前后上下颌牙弓长度、磨牙间宽度在模型上的变化有统计学意义。头颅侧位片表现上下切牙内收,磨牙前移。下颌切牙压低,磨牙有一定程度的伸长。牙弓长度变化在模型及X线头影测量上具有相关性(P<0.01)。结论(1)正畸治疗后牙齿位置在头颅侧位片上变化与模型上实际变化呈正相关;(2)X线头影测量分析一些间接测量的项目,在某些情况下与牙、颌、面的实际情况有一定的差异。

Theory and practice of hull dynamic deformation law and heading angle transfer error correction

In order to meet the demand of high-precision heading angle transmission in the transfer alignment of inertial navigation system on moving base,the analytical function relationship between the hull deforma-tion and the turning angular velocity and angular acceleration was derived by using the classical beam theory based on the analysis of the equivalent load exerted by the hydrodynamic force and inertia force on the hull structure during the turning process under the combined action of the steering rudder mo-ment and wave force.The objective law between the angular motion and the azimuth deformation angle of the hull under the combined action of maneuvering and sea waves was revealed.Finally,the correc-tion coefficients were determined according to the left turn and right turn motions of the hull by using the measured data of the ship in the sea trial during the S-shape maneuvering navigation,and the az-imuth deformation angle correction was completed.The results indicated that the application of the Qu’s bending deformation correction formula could greatly reduce the influence of the hull flexural deforma-tion on the heading angle accuracy,meet the needs of high-precision heading angle transmission,and fully verify the correctness of the hull azimuth deformation law and the heading angle transmission er-ror correction theory.This theory and method provided technical support for establishing high-precision distributed digital reference in the field of transfer alignment of inertial navigation on moving base and the application of heading angle transfer of other shipborne equipment.

Effects of the windshield inclination angle on head/brain injuries in car-to-pedestrian collisions using computational biomechanics models

Car-to-pedestrian collision(CPC)accidents occur frequently,and pedestrians often suffer serious head/brain injuries.One major cause is the primary impact with the windshield.Here,we use an umerical sim ulation method to study the influence of the windshield in-clination angle of a passenger car on pedestrian head/brain injury due to CPC accidents.The range of the windshield inclination angle was set at 24°-50°,with an interval of 2°.The results show that the windshield angle significantly affects the pedestrian kine-matics and exerts different effects on the head injury when evaluating with various head injury criteria.Regarding the head peak linear/rotational acceleration and acceleration-based head injury criterion(HIC)/rotational injury criterion(RIC),the predictions at the secondary impact stage have no clear relationship with the windshield angle(R^(2)=0.04,0.07,0.03 and 0.26,respectively)and their distributions are scattered.In the primary impact,the peak linear acceleration and HIC show a weak trend of first decreasing and then increasing with the increasing of the windshield angle,and the rotational acceleration and RIC tend to remain relatively con-stant.Regarding the cum ulative strain dama ge measure(CSDM)criterion,the predictions at the primary impact are slightly lower than those at the secondary impact,and the trend of first decreasing and then increasing with the increase in the windshield angle is observed at both impact stages.When the windshield inclination angle is approximately 32°-40°,the head injury severity in both impact phases is generally lower than that predicted at other windshield angles.

Numerical study of attack angle characteristics for integrated hypersonic vehicle

The two-dimensional coupled implicit Navier-Stokes equations and standard k-ε viscous models are used to simulate the angle of attack characteristics of an inte- grated hypersonic vehicle with a hark head configuration under three kinds of working conditions： inlet cut-off, engine through-flow, and engine ignition. Influence of each com- ponent on aero-propulsive performance of the vehicle is discussed. It is concluded that the longitudinal static stability of the vehicle is good, and there is enough lift-to-drag ratio to satisfy the flying requirement of the vehicle. At the same time, it is important to change configurations of engine and upper surface of airframe to improve aero-propulsive ~erformance of the vehicle.

Subchondral fatigue fracture of the femoral head in young military recruits:Potential risk factors

BACKGROUND Subchondral fatigue fracture of the femoral head(SFFFH)mainly occurs in young military recruits and might be confused with osteonecrosis of the femoral head.However,less research focuses on the risk factor for SFFFH.AIM To evaluate the intrinsic risk factors for SFFFH in young military recruits.METHODS X-ray and magnetic resonance imaging data were used for analysis.Acetabular anteversion of the superior acetabulum,acetabular anteversion of the center of the acetabulum(AVcen),anterior acetabular sector angle(AASA),posterior acetabular sector angle,superior acetabular sector angle,neck-shaft angle(NSA),inferior iliac angle(IIA),and ischiopubic angle were calculated.Then,logistic regression,receiver operating characteristic curve analysis,and independent samples t-test were performed to identify the risk factors for SFFFH.RESULTS Based on the results of logistic regression,age[odds ratio(OR):1.33;95%confidence interval(95%CI):1.12-1.65;P=0.0031]and treatment timing(OR:0.86;95%CI:0.75-0.96;P=0.015)could be considered as the indicators for SFFFH.AVcen(P=0.0334),AASA(P=0.0002),NSA(P=0.0007),and IIA(P=0.0316)were considered to have statistical significance.Further,AVcen(OR:1.41;95%CI:1.04-1.95)and AASA(OR:1.44;95%CI:1.21-1.77),especially AASA(area under curve:66.6%),should be paid much more attention due to the higher OR than other indicators.CONCLUSION We have for the first time unveiled that AASA and age could be key risk factors for SFFFH,which further verifies that deficient anterior coverage of the acetabulum might be the main cause of SFFFH.

基于自适应ZUPT与航向角误差修正的INS约束算法

为提高行人惯性导航系统(INS)的定位精度,提出了一种基于自适应零速修正算法(ZUPT)与航向角误差修正的INS约束算法。首先,利用基于广义似然比的零速检测阈值与检验统计量的特征值建立关系式,实现对零速检测阈值的自适应调整。然后,对INS解算位置建立线性回归模型,结合主航向与解算航向的航向差,根据行人运动类型构建观测向量和观测矩阵,对INS误差进行修正。最后,经实验验证,当行人在复杂路线变速运动时,相较于固定阈值的零速检测算法和主航向修正算法,所提算法的解算轨迹更接近真实轨迹,平均闭环误差从3.31%D减小至1.45%D,有效提高了INS定位精度,具有较好的工程应用价值。

头部支撑面角对连杆螺栓与大头盖接触应力的影响

国标六角法兰面螺栓对螺栓支撑面角度范围提出设计指导,但没有具体指出最佳角度,且其对螺栓预紧力及支撑面应力的影响尚无明确结论。通过建立发动机连杆螺栓的精细拧紧有限元仿真模型,并利用Yamamoto解析法验证了连杆螺栓有限元模型的准确性。研究了螺栓头部支撑面角对拧紧载荷下连杆螺栓预紧力和应力分布的影响,同时通过计算疲劳安全系数对螺栓头部支撑面的结构可靠性进行综合评估。结果表明:螺栓头部支撑面角取0.5°为最佳;提出了带有U型沉割槽的连杆螺栓结构模型,优化后的螺栓结构在螺栓头部与螺杆结合处的平均应力下降16.2%,平均疲劳安全系数提高19.6%。

基于转向架航向角的既有铁路平面线形识别方法研究

轨道平面线形识别是解算轨道不平顺的基础。针对外挂式动态轨道检查仪的实际需要,提出一种基于转向架航向角的铁路平面线形识别方法。首先,通过分段试拟合判定准则自动识别各测点所属线元类型和特征点数量;然后,建立基于转向架航向角的平面线形特征点优化模型;最后,结合云模型改进传统遗传算法的搜索策略提出云遗传算法,实现铁路平面线形精确识别。研究表明,平面线路曲线特征点识别偏差在4 m以内,线形识别准确度均达到97%以上,满足外挂式动态轨道检查仪对轨道不平顺解算的精度要求。

基于目标概略航向的反舰导弹纯方位攻击法

为充分利用累积的目标历史方位测量信息,提高反舰导弹纯方位攻击时的目标捕获概率,在估计目标概略航向的基础上,采用几何分析和三角函数分解方法,建立了导弹纯方位攻击提前转向角与目标速度、导弹速度间的解析关系式,获得了导弹末制导雷达百分之百捕获目标区域半径计算模型和目标捕获概率的计算方法。仿真结果表明,通过设置提前转向角可显著提高反舰导弹末制导雷达目标捕获概率,增大百分之百捕获目标区域半径,有助于提升反舰导弹作战效能。

基于行船视距的船舶会遇安全距离研究

近年来船舶交通流量大幅增加,船舶会遇愈加频繁。为降低船舶会遇避让时的碰撞危险,在行车视距基础上,提出行船视距的概念,并引入航速、避让航向角等参数,构建基于行船视距的船舶领域模型,船舶采取避让操作时,可利用该模型判断应与他船保持的安全距离和最佳航速及避让航向角。从仿真结果发现:船舶追越时应尽量与他船保持3.5倍船长以上距离,并在船尾与他船达到2倍船长以上距离时回到原航向;对遇时应尽量与他船保持7倍船长以上距离采取避让,如果航道宽裕,避让时应尽量与他船横距保持1.8倍船长以上,如果航道较窄,也应尽量保证船舶在可航水域内进行大角度避让,并与他船横距保持0.72倍船长以上。研究结果可为实际船舶避让提供指导建议。

痉挛型脑性瘫痪儿童腰椎与髋关节发育的关系

背景:目前多数学者认为,幼年就患有严重脊柱畸形的脑性瘫痪患儿(<15岁)其脊柱畸形可能存在更高的进展风险,其原因可能来源于骨盆倾斜、疼痛等导致的行动时失衡。目的:探究痉挛型脑性瘫痪儿童腰椎发育与髋关节发育的关系。方法:回顾性分析2014年1月至2021年12月就诊于北京中医药大学东直门医院的痉挛型脑性瘫痪患儿102例。所有入院患儿均完成骨盆正位及腰椎侧位X射线片,通过骨盆正位X射线片测量股骨头偏移百分比、中心边缘角、颈干角、髋臼指数,通过腰椎侧位X射线片测量矢状位Cobb角、骶骨倾斜角、弓顶距、腰椎前凸指数,进一步分析两类指标的相关性。将所有患儿依据股骨头偏移百分比分为正常组、风险组、髋关节半脱位组及髋关节全脱位组,评价不同组间腰椎指标的差异。结果与结论:①Pearson相关性分析表明,股骨头偏移百分比和腰椎矢状位Cobb角、弓顶距呈中等程度正相关,与腰椎前凸指数呈弱正相关;中心边缘角与弓顶距呈中等程度负相关,与矢状位Cobb角呈弱负相关;颈干角与矢状位Cobb角、前凸指数呈极弱正相关或不相关;髋臼指数与矢状位Cobb角、弓顶距呈弱正相关;其余指标间未发现具有相关性;②根据股骨头偏移百分比将患儿分为4组,其中正常组25例,风险组41例,髋关节半脱位组27例,髋关节全脱位组9例;风险组、髋关节半脱位组、髋关节全脱位组矢状位Cobb角均较正常组明显增加,且逐组递增,组间两两比较差异均有显著性意义(P<0.05);风险组、髋关节半脱位组前凸指数较正常组明显增加,两两比较差异有显著性意义(P<0.05),髋关节全脱位组较正常组存在升高趋势;髋关节半脱位组、髋关节全脱位组弓顶距较正常组明显增加,差异有显著性意义(P<0.05),且存在逐级递增趋势;各组间骶骨倾斜角两两比较差异无显著性意义;③提示脑性瘫痪患儿腰椎发育与骨盆髋关节发育有密切关联,尤以腰椎前凸畸形和髋关节脱位畸形的关系最明显。

基于YOLOv8L遥感图像旋转目标检测

针对遥感图像复杂背景下的目标(如船舶、飞机等)具有朝向任意、尺度变化较大、数量多、目标排列密集等特点,提出一种基于改进YOLOv8L的旋转目标检测算法,用带有角度的旋转框能够更加精确定位目标。首先,在网络Head部分增加解耦角度预测头,预测目标的角度信息;其次,融合坐标注意力机制模块提高模型抑制噪声的能力;最后,在Neck部分引入自适应空间特征融合模块,抑制不同尺度特征图之间融合特征信息时的不一致性,保留有效的信息并进行融合。实验结果表明,所提算法在DOTA数据集上的检测精度达到了73.85%,较原有YOLOv8L模型提升了3.53%。

双髋关节MRI预测股骨头坏死塌陷风险

背景:MRI是诊断股骨头坏死的金标准,以往基于MRI图像预测股骨头坏死塌陷的方法多需要冠状面、矢状面图像联合评估。然而由于股骨头坏死好发于双侧,临床上大多医院检查时多行双侧髋关节MRI扫描,但双髋扫描仅可查看冠状面及横断面图像,难以获取矢状面图像,从而影响塌陷风险的评估。因此,建立一种应用双髋MRI可获取的图像评估早期股骨头坏死塌陷风险的方法有一定的临床实用价值。目的:建立一种应用双髋关节MRI冠状面与横断面图像评估股骨头坏死塌陷风险的方法。方法:回顾性分析2017年10月至2019年10月在西安交通大学附属红会医院门诊确诊的早期股骨头坏死患者111例(181髋)的病历资料。根据末次随访时股骨头塌陷情况分为2组,其中塌陷组69髋,未塌陷组112髋。在MRI影像系统上测量正中冠状面、横断面或其上下各一个层面图像上的坏死范围角度,以冠状面、横断面上坏死角两角之和作为联合坏死角,并取每髋3种联合坏死角的平均值得到每髋的平均联合坏死角。最后,分析3种联合坏死角及平均联合坏死角与股骨头坏死塌陷的相关性,利用受试者工作特征曲线评价4种联合坏死角预测塌陷的特异性与敏感性。结果与结论:①末次随访69髋(38.1%)发生股骨头塌陷,纳入塌陷组;112髋(61.9%)未发生塌陷进展,纳入非塌陷组;②塌陷组与未塌陷组在ARCO分期方面比较差异有显著性意义(P<0.001);在年龄、体质量指数、随访时间、性别分布、发病侧别、致病因素等方面比较差异均无显著性意义(P>0.05);③独立样本t检验结果提示,4种联合坏死角均与塌陷显著相关(P<0.0001);且ARCOⅠ期、Ⅱ期中塌陷组与未塌陷组患者的联合坏死角相比差异均有显著性意义(P<0.0001);④在受试者工作特征分析中,平均联合坏死角曲线下面积大于正中下一层面、正中层面、正中上一层面上的联合坏死角;⑤平均联合坏死角塌陷预测准确度高于正中下一层面、正中层面、正中上一层面上的联合坏死角;⑥提示平均联合坏死角对股骨头坏死塌陷风险的预测精准度较高,临床实用性较强,可考虑使用该方法对股骨头坏死塌陷风险进行预测。

圆形管渠直角分支口处水力特征试验研究

管网分水是管网运行的重要模式,为探索圆形管渠直角分水口附近处的基本水流特征,采用DN315的PVC圆管,在5种流量、5种分流比条件下开展管渠直角分水口过流试验,测量了分水口处局部水深,采用多普勒声学流速仪(ADV)测量了典型断面上的三维瞬时流速,分析了管渠直角分水口典型断面的时均流速分布及水头损失。研究表明:分水口附近主管水面线大体呈现先减小后增加的趋势,大流量下水面线壅高程度高,分流比对口门处水面线影响较大。纵向流速经过分水口流速降低,而横向流速增加。分水口上下游纵向和横向流速呈对称分布,而在分水口区域靠近分水口侧数值较大。纵向流速垂向呈现抛物线型分布,分水口中轴断面处出现负值即存在回流区;横向流速垂向呈内凹型分布,不存在负值即不存在横向环流。水平流场的分流宽度随分流比的增大而增大,断面中层分流宽度大于其他层。水头损失系数在流向支管向远大于流向主管向,在分流比为0.4、流量为50 L/s总水头损失系数最小。本研究对于指导管网设计及运行具有重要意义。

股骨头前、外侧保留角和联合保留角在股骨头坏死经髋关节外科脱位打压植骨支撑术适应证选择中的作用

目的:探讨股骨头前侧保留角(anterior preserved angle,APA)、外侧保留角(lateral preserved angle,LPA)和联合保留角(combined preserved angle,CPA)在股骨头坏死(osteonecrosis of the femoral head,ONFH)经髋关节外科脱位打压植骨支撑术适应证选择中的作用。方法:以2020年1月至2022年12月在广州中医药大学第三附属医院接受经髋关节外科脱位打压植骨支撑术治疗的ONFH患者为研究对象。收集患者的性别、年龄、ONFH分期和分型,以及手术前后、随访期间双侧髋关节蛙位和正位X线片等信息。在患者术前双侧髋关节蛙位和正位X线片上分别测量股骨头APA和LPA,二角之和为股骨头CPA。以行全髋关节置换术为终点事件,采用Kaplan-Meier法分析经髋关节外科脱位打压植骨支撑术后股骨头生存情况;采用受试者工作特征(receiver operating characteristic,ROC)曲线确定股骨头APA、LPA和CPA预测经髋关节外科脱位打压植骨支撑术治疗失败的最佳临界值,并根据此临界值进行二分类后采用Kaplan-Meier法分析其对股骨头生存情况的预测效果。结果:(1)一般情况。共纳入109例患者,随访时间8~47个月,中位数25个月。患者术前股骨头APA 43.71°±14.43°,LPA 53.08°±15.62°,CPA 96.79°±24.60°。随访期间,18髋改行全髋关节置换术,其中17髋发生在经髋关节外科脱位打压植骨支撑术后2年内。(2)经髋关节外科脱位打压植骨支撑术后股骨头生存情况。术后1年、2年和3年股骨头生存率分别为97.5%、86.1%和81.6%。(3)股骨头APA、LPA和CPA对经髋关节外科脱位打压植骨支撑术治疗失败的预测价值评价结果。股骨头APA、LPA和CPA预测经髋关节外科脱位打压植骨支撑术治疗失败的曲线下面积分别为0.835、0.765、0.854,敏感度分别为67.3%、75.2%、91.1%,特异度分别为88.9%、72.2%、72.2%,临界值分别为39.5°、46.5°、75.0°。(4)股骨头APA、LPA和CPA对经髋关节外科脱位打压植骨支撑术后股骨头生存情况的预测结果。与术前股骨头APA≤39.5°、LPA≤46.5°、CPA≤75.0°相比,术前股骨头APA>39.5°、LPA>46.5°、CPA>75.0°时,股骨头生存率更高。结论:股骨头APA、LPA和CPA可用于指导ONFH经髋关节外科脱位打压植骨支撑术适应证的选择,且术前股骨头APA>39.5°、LPA>46.5°、CPA>75.0°的患者有望获得更好的手术疗效。

初次单侧全髋关节置换后骨盆倾斜转归的因素分析

背景:骨盆倾斜多见于髋关节疾病,也是全髋关节置换后常见的功能问题。目的:探讨股骨头坏死患者单侧全髋关节置换后骨盆倾斜的发生机制与恢复情况。方法:回顾性收集2021年6月至2023年2月广州中医药大学第一附属医院骨伤中心股骨头坏死科收治的100例股骨头坏死且接受单侧全髋关节置换患者的临床资料,根据术后3 d时骨盆倾斜严重程度分为3组,A组(<2°)48例,B组(2°-3°)34例,C组(>3°)18例。统计并比较3组患者术前、术后骨盆冠状面倾斜角度、双侧臀中肌长度、股骨头旋转中心高度以及双侧臀中肌长度差值、股骨头旋转中心高度差值、骨盆倾斜角度变化比值。采用皮尔逊相关系数检验术后骨盆倾斜角度与其他指标的相关性。结果与结论:①术后短期内发生骨盆倾斜加重;②术后3 d至术后1个月时段骨盆倾斜角度变化比值组间存在差异,C组>B组>A组;术后1-3个月时段C组与其他各组存在差异,C组变化比值最小;术后3 d至术后3个月时段组间变化比值无差异;③双侧臀中肌差值术后逐渐减小,术后3个月时双侧臀中肌比较无差异;④术后双侧旋转中心差值增大,术后3个月时双侧高度差值小于术前;⑤术后3 d时骨盆倾斜角度、病程与术后3个月骨盆倾斜角度呈显著相关性(均P=0.000),术前双侧臀中肌差值与术后3 d时骨盆倾斜角度呈显著相关性(P=0.006);⑥提示股骨头坏死患者全髋关节置换后发生功能性骨盆倾斜;术后骨盆倾斜的矫正是基于术后功能性骨盆倾斜角度的适应性恢复;功能性骨盆倾斜的产生是以术后短期骨性结构重建、软组织积累性损害存续为基础的机体代偿适应。

基于云层去除的偏振光导航应用研究

传统的导航系统因其自身的技术缺陷而远远不能满足人们日常的导航需求,仿生式偏振光导航应运而生。在传统的图像式偏振光导航系统中,云层遮挡往往会对偏振光信息的采集造成严重影响,从而影响到航向角的准确解算,极大程度限制了偏振光导航的运用范围。为了克服这一困难,文中引入生成对抗神经网络,在生成器与鉴别器之间不断迭代反馈,对采集到的云层图像进行去云层处理,有效地恢复了被云层遮挡的偏振光信息。经过大量实验验证,成功将航向角误差从2.3706°降低至0.6067°,使其导航精度提升了74.41%。实验结果不仅验证了该方法的有效性,也展示了生成对抗网络在图像修复方面的强大之处,对图像式偏振光导航的发展提供了新的思路。