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Analysis of video head impulse test saccades data in patients with vestibular migraine or probable vestibular migraine 被引量:5
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作者 Yi Du Xingjian Liu +2 位作者 Lili Ren Yu Wang Ziming Wu 《Journal of Otology》 CSCD 2022年第4期197-202,共6页
Objective:Saccades accompanied by normal gain in video head impulse tests(vHIT)are often observed in patients with vestibular migraine(VM).However,they are not considered as an independent indicator,reducing their uti... Objective:Saccades accompanied by normal gain in video head impulse tests(vHIT)are often observed in patients with vestibular migraine(VM).However,they are not considered as an independent indicator,reducing their utility in diagnosing VM.To better understand clinical features of VM,it is necessary to understand raw saccades data.Methods:Fourteen patients with confirmed VM,45 patients with probable VM(p-VM)and 14 agematched healthy volunteers were included in this study.Clinical findings related to spontaneous nystagmus(SN),positional nystagmus(PN),head-shaking nystagmus(HSN),caloric test and vHIT were recorded.Raw saccades data were exported and numbered by their sequences,and their features analyzed.Results:VM patients showed no SN,PN or HSN,and less than half of them showed unilateral weakness(UW)on caloric test.The first saccades from lateral semicircular canal stimulation were the most predominant for both left and right sides.Neither velocity nor time parameters were significantly different when compared between the two sides.Most VM patients(86%)exhibited small saccades,around 35%of the head peak velocity,with a latency of 200e400 ms.Characteristics of saccades were similar in patients with p-VM.Only four normal subjects showed saccades,all unilateral and seemingly random.Conclusions:Small saccades involving bilateral semicircular canals with a scattered distribution pattern are common in patients with VM and p-VM. 展开更多
关键词 Vestibular migraine Probable vestibular migraine Video head impulse test SACCADE Data analysis
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Saccades of video head impulse test in Meniere's disease and Vestibular Migraine: What can we learn from? 被引量:3
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作者 Yi Du Xingjian Liu +4 位作者 Lili Ren Yu Wang Fei Ji Weiwei Guo Ziming Wu 《Journal of Otology》 CSCD 2023年第2期79-84,共6页
Background:Saccades are often observed on video head impulse tests(vHIT)in patients with Meniere's Disease(MD)and Vestibular Migraine(VM).However,their saccadic features are not fully described.Objective:This stud... Background:Saccades are often observed on video head impulse tests(vHIT)in patients with Meniere's Disease(MD)and Vestibular Migraine(VM).However,their saccadic features are not fully described.Objective:This study aims to identify the saccades characteristics of MD and VM.Methods:75 VM patients and 103 definite unilateral MD patients were enrolled in this study.First raw saccades were exported and analyzed.The VM patients were divided into left and right based on their ears,while the MD patients were separated into affected and unaffected subgroups based on their audiograms and symptoms.Results:The MD patients have more saccades on the affected side(85%vs.69%),and saccade velocity is more consistent than the contralateral side(shown by the coefficient of variation).The saccades occurrence rates on both sides are similar in VM(77%vs.76%),as are other saccadic parameters.The MD patients have more significant inter-aural differences than the VM patients,manifested in higher velocity(p-value 0.000),earlier arriving(p-value 0.010),and more time-domain gathered(p-value 0.003)on the affected side.Conclusions:Bilateral saccades are commonly observed in MD and VM.In contrast to MD,saccades on VM are subtle,scattered,and late-arrived.Furthermore,the MD patients showed inconsistent saccadic distribution with more velocity-uniform saccades on the affected side. 展开更多
关键词 Meniere's disease Vestibular migraine SACCADES Video head impulse test Differential diagnosis
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Syncope as a health risk for soldiers: Influence of medical history and clinical findings on the sensitivity of head-up tilt table testing 被引量:1
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作者 Hans-Joachim Gilfrich Lena Marie Heidelmann +2 位作者 Franziska Grube Hagen Frickmann Sven Andreas Jungblut 《Journal of Medical Colleges of PLA(China)》 CAS 2015年第2期82-90,共9页
Background: Syncope is a relevant health problem in military environments. Reliable diagnosis is challenging. Tilt table testing is an important tool for syncope diagnosis. The aim of this study was to determine wheth... Background: Syncope is a relevant health problem in military environments. Reliable diagnosis is challenging. Tilt table testing is an important tool for syncope diagnosis. The aim of this study was to determine whether signs such as prodromal symptoms, co-morbidity, frequency of syncopal events, body length, body mass index, and electrocardiography(ECG) abnormalities can be used to predict the success of tilt table testing at diagnosing syncope.Methods: Data from 100 patients with histories of syncope or pre-syncope, who were diagnosed using head-up tilt table testing, were retrospectively analyzed in a cross-sectional analysis. The diagnostic procedure was based upon a modified version of the Westminster protocol without any pharmacological provocation. Results: Patients showing pathological reaction patterns during tilt table testing suffered from prodromal symptoms, such as dizziness and sweating, significantly more often. The patients reported more injuries resulting from syncopal events and more previous syncopal events, and the prevalence of co-morbidity was greater among patients presenting negative findings during tilt testing. An asthenic-leptosomal physique was not confirmed as a risk factor for syncopal events as is the case for idiopathic arterial hypotension. However, patients with pathological reaction patterns during tilt table testing were significantly taller. This finding was detected for both females and males. No significant predictors were found in the ECG patterns of patients showing syncope during tilt table testing.Conclusions: Frequency of prior syncope and prodromal symptoms, and increased body length with an otherwise good state of health influence the predictive value of tilt table testing for syncope diagnosis. In particular, if these factors are present, tilt table testing should be considered part of the diagnostic algorithm for soldiers with recurrent syncope. 展开更多
关键词 SYNCOPE head-up TILT testing PREDICTOR SOLDIERS Assessment HYPOTENSION
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Evaluation on Effectiveness of a New System as well as Analysis on Optimal Horizontal Eye Position for Vertical Video Head Impulse Test
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作者 Tao JIANG Fei LI +5 位作者 Jing YU Ruo-nan HUANG Rui GAO Chen-yong SHANG Jian-hua ZHUANG Wen-yan LI 《Current Medical Science》 2021年第4期705-711,共7页
Objective To compare the performances among three different systems for video head impulse test(vHIT),and to identify an optimal target angle for precisely evaluating the function of vertical semicircular canals in vH... Objective To compare the performances among three different systems for video head impulse test(vHIT),and to identify an optimal target angle for precisely evaluating the function of vertical semicircular canals in vHIT.Methods A two-center prospective study was done.Participants were sit 1.2 m away from the wall in a noise-proved room that dedicated for vHIT experiments.During the comparison experiments,similar settings were ensured in both hospitals,with the same distance to wall and angle of staring.For each equipment,the procedures followed the developers’recommendations.The same examiner performed the comparison between two systems in one location.For the eye-position projects,targets were placed on the wall sequentially at the pre-marked lines for different angles.For the comparison projects,9 and 13 participants were recruited,respectively.Any participant with otologic or vestibular disorders was excluded.A total of 26 healthy participants were recruited in the eye-position experiments,16 of which were further involved in inter-examiner tests.Results Our evaluations of three different systems showed that a new vHIT system,VertiGoggles®ZT-VNG-I(VG)performed as good as the long-tested Otometrics®ICS impulse(Oto)and EyeSeeCam®(ESC).During the comparison,we validated 25-degree,instead of right ahead at 0 degree,is a better place to set the targets when torsion was applied at vertical semicircular canal planes.Conclusion The new VG system is good for clinical practices.Furthermore,we proposed a new protocol to set the targets 25 degrees from right ahead after tilting head 45 degrees to evaluate vertical canals during vHIT. 展开更多
关键词 video head impulse test target angle vestibular disorder system comparison GOGGLES
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The Changes of Baroreflex Sensitivity During Head-up Tilt Test and Its Clinical Significance in the Patients with Vasovagal Syncope
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作者 胡兆霆 吕艳青 杨钧国 《South China Journal of Cardiology》 CAS 2001年第2期65-68,共4页
Objective To study thechanges of baroreflex sensitivity (BRS) during head - up tilt test (HUT) in patients with vasovagal syncope (VS), and to examine the relationship between baroreflex sensitivity and neurohormonal ... Objective To study thechanges of baroreflex sensitivity (BRS) during head - up tilt test (HUT) in patients with vasovagal syncope (VS), and to examine the relationship between baroreflex sensitivity and neurohormonal factors. Furthermore, to investigate the effects of the changes of BRS on VS. Methods Forty - two patients with unexplained syncope (Among the 42 patients, there were 22 patients with positive HUT and 20 patients with negative HUT respectively) and 20 healthy volunteers (with negative HUT) underwent passive head - up tilt testing, Ante-cubital vein blood samples were taken before and after HUT, or at syncope. The fasting plasma endothelin , serum nitric oxide (NO), serum NE were measured, the BRS was assessed on the basis of the linear regression slope the RR interval versus systolic arterial blood pressure during the increment in blood pressure after intravenous administration of phenylephrine. Results (1) During the syncope, the BRS significantly reduced in HUT(+) group than baseline. At the end of tilt, the level of plasma ET, serum NO in patients with positive HUT significantly increased compared with baseline or normal controls, and the plasma concentration of NE also had the trend of increase. (2) By multiple regression analysis, a significant negative correlation was found between baroreceptor sensitivity and the plasma ET, NO at the end of HUT in patients with positive HUT, but there was no relationship between BRS and NE. Conclusions During the syncope occure, the BRS in patients with VS decreased significantly compared with normal controls. The abnormal plasma ET, NO concen-tration might contribute to the mechanism of VS. 展开更多
关键词 Vasovagal syncope head - up tilt test Endothelin Nitric oxide Baroreflex Sensitivity
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Syncope as a health risk for soldiers-influence of medical history and clinical findings on the sensitivity of head-up tilt table testing
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作者 Hans-Joachim Gilfrich Lena Marie Heidelmann +2 位作者 Franziska Grube Hagen Frickmann Sven Andreas Jungblut 《Journal of Medical Colleges of PLA(China)》 CAS 2016年第1期34-42,共9页
Background:Syncope is a relevant health problem in military environments.Reliable diagnosis is challenging.Tilt table testing is an important tool for syncope diagnosis.The aim of this study was to determine whether s... Background:Syncope is a relevant health problem in military environments.Reliable diagnosis is challenging.Tilt table testing is an important tool for syncope diagnosis.The aim of this study was to determine whether signs such as prodromal symptoms,co-morbidity,frequency of syncopal events,body length,body mass index,and electrocardiography abnormalities can be used to predict the success of tilt table testing at diagnosing syncope.Methods:Data from 100 patients with histories of syncope or pre-syncope,who were diagnosed using head-up tilt table testing,were retrospectively analyzed in a cross-sectional analysis.The diagnostic procedure was based upon a modified version of the Westminster protocol without any pharmacological provocation.Results:Patients showing pathological reaction patterns during tilt table testing suffered from prodromal symptoms,such as dizziness and sweating,significantly more often.The patients reported more injuries resulting from syncopal events and more previous syncopal events,and the prevalence of co-morbidity was greater among patients presenting negative findings during tilt testing.An asthenic-leptosomal physique was not confirmed as a risk factor for syncopal events as is the case for idiopathic arterial hypotension.However,patients with pathological reaction patterns during tilt table testing were significantly taller.This finding was detected for both females and males.No significant predictors were found in the electrocardiogram patterns of patients showing syncope during tilt table testing.Conclusions:Frequency of prior syncope and prodromal symptoms,and increased body length with an otherwise good state of health influence the predictive value of tilt table testing for syncope diagnosis.In particular,if these factors are present,tilt table testing should be considered part of the diagnostic algorithm for soldiers with recurrent syncope. 展开更多
关键词 SYNCOPE head-up TILT testing PREDICTOR SOLDIERS Assessment HYPOTENSION
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Age and Sex Distribution of Patients with Vasovagal Syncope Undergoing Head-up Tilt Table Test: 7-Year Audit
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作者 SALIM Mohamed KEBBATI A. Hafid 《Wuhan University Journal of Natural Sciences》 CAS 2012年第4期364-368,共5页
To investigate age and sex distribution of vasovagal syncope (VVS) patients undergoing head-up tilt table test (HUTT) at a tertiary hospital. The details of syncope patients who underwent HUTT at our department of... To investigate age and sex distribution of vasovagal syncope (VVS) patients undergoing head-up tilt table test (HUTT) at a tertiary hospital. The details of syncope patients who underwent HUTT at our department of cardiac function from January 2004 to December 2010 were reviewed. Of the 1 799 patients who underwent the HUTT, 854 tested positive, of which 558 (65.3%) were women, which were more than the women in the negative group (450, 47.6%) (p〈0.05). VVS patients showed a bimodal age distribution between 11 and 20 years of age and in the fourth decade. In almost all age groups, mixed response was the highest compared with vasodepressor and cardioinhibitory. VVS patients who underwent HUTT indicate bimodal distribution peaking before the second decade and the fourth decade. The incidence of females was twice that of males before the sixth decade, and old age occupies a small percentage of VVS with no other comorbidities. 展开更多
关键词 age SEX vasovagal syncope head-up tilt table test
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The Changes of Heart Rate Power Spectral Density during Head-up Tilt Test
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作者 陈椿 张馥敏 +1 位作者 黄元铸 马文珠 《The Journal of Biomedical Research》 CAS 1998年第1期21-24,共4页
To study the role of autonomic nervous system in the period of developing syncope induced by head-up tilt test(HUT), we analysed the changes of heart rate power spectral density(HRPSD) in 50 patients with unexplained ... To study the role of autonomic nervous system in the period of developing syncope induced by head-up tilt test(HUT), we analysed the changes of heart rate power spectral density(HRPSD) in 50 patients with unexplained syncope, including 15 positive patients (Group 1) and 35 negative patients(Group 2), and 15 negative healthy persons(Group 3) in 5 minute periods before and after tilting and 5 minutes before the end of test. HRPSD and their changes in total(T), very low-frequence(VLF), low-frequence(LF), high-frequence(HF) and the ratio of low/high frequence(LF/HF) were similar (P>0.05) 5 minutes before and after tilting among three groups. Five minutes before the end of test, Group 1 had obvious increase of T, VLF, LF and LF/HF while Group 2 and 3 had not such significant changes. There was significant difference(P<0.01) compared Group 1 with Group 2, 3. The results showed that the abnormal regulatory function of autonomic nervous system played an important role in the mechanism of symcope induced by HUT, the positive group had abnormal increase of sympathetic tone and imbalance of sympathetic/parasympathetic neural tone before syncope appeared. 展开更多
关键词 head-up tilt test SYNCOPE heart rate power spectral density autonomic nervous system
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某施工现场接尘人员防尘口罩适合性与头面部尺寸关系研究
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作者 陈霞 刘晓旭 +3 位作者 李晓琴 张意 赵子贺 张雪艳 《中华劳动卫生职业病杂志》 北大核心 2026年第1期37-42,共6页
目的探讨接尘人员防尘口罩适合性与其头面部尺寸之间的关系,为接尘人员筛选适合的防护口罩。方法于2023年7月,采用整群抽样,选择施工现场全部接尘人员(300人)作为研究对象。使用Artec EVA手持三维扫描仪及其软件完成21项头面部尺寸指标... 目的探讨接尘人员防尘口罩适合性与其头面部尺寸之间的关系,为接尘人员筛选适合的防护口罩。方法于2023年7月,采用整群抽样,选择施工现场全部接尘人员(300人)作为研究对象。使用Artec EVA手持三维扫描仪及其软件完成21项头面部尺寸指标测量,每名研究对象选择折叠形和拱形口罩各1种进行适合性检验,采用χ^(2)检验和多因素logistic回归分析头面部尺寸指标与口罩适合性间的关系。结果300名接尘人员共进行适合性检验600人次,总通过率为23.50%(141/600)。不同类型的口罩通过率不同,拱形口罩通过率(36.00%,108/300)明显高于折叠形(11.00%,33/300),差异有统计学意义(χ^(2)=52.15,P<0.001)。头面部尺寸分栏总体覆盖率为75.00%(225/300),拱形口罩在不同分栏中的适合性检验通过率差异有统计学意义(χ^(2)=18.92,P<0.05)。多因素logistic回归结果显示,体质指数(BMI)、形态面长、鼻宽和口罩形状是口罩适合性的主要影响因素(OR=1.08、1.58、2.57、5.27,P<0.05)。结论口罩适合性的影响因素主要为BMI、口罩形状、形态面长和鼻宽,建议职业人群首次使用防尘口罩前进行适合性检验。 展开更多
关键词 粉尘 施工现场 防尘口罩 适合性检验 头面部尺寸
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煤渣脏污对铁路道砟层渗透性能影响研究
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作者 刘鉴兴 刘凯 +3 位作者 寇磊 徐昕阳 陈嵘 王平 《铁道学报》 北大核心 2026年第2期116-124,共9页
铁路有砟轨道是一种广泛采用的运煤方式。煤渣的侵入极大影响了有砟道床的排水性能。对多种煤渣脏污程度的道砟层进行常水头渗透试验和渗流形式分析,采用校正后的离散元-计算流体力学(DEM-CFD)双向耦合模型模拟脏污道砟层的渗透性能,进... 铁路有砟轨道是一种广泛采用的运煤方式。煤渣的侵入极大影响了有砟道床的排水性能。对多种煤渣脏污程度的道砟层进行常水头渗透试验和渗流形式分析,采用校正后的离散元-计算流体力学(DEM-CFD)双向耦合模型模拟脏污道砟层的渗透性能,进一步研究煤渣脏污道砟层的细观排水特性。物理试验和仿真结果表明,清洁道砟层的渗透模式为显著的湍流,但随着煤渣脏污程度增大,样品的渗透模式呈现出由湍流状态向线性层流状态转变的趋势。同时,样品的渗透系数显著减小。在细观视角方面,煤渣增多使得道砟层内部动态水压数值减小,水压整体的分布亦趋于均匀。此外,脏污道砟层内较小的空隙值及空隙率增大了混合体对水流流向和流速的限制作用。研究结果有助于了解道砟层的排水性能受煤渣脏污程度而产生的变化,进一步完善运煤有砟轨道的清筛和维护周期。 展开更多
关键词 铁路道砟 煤渣脏污 渗透性能 常水头试验 DEM-CFD耦合
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急性前庭神经炎患者自发性眼震和前庭功能的相关性分析
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作者 温玉 刘翠萍 钟翠萍 《川北医学院学报》 2026年第2期189-192,205,共5页
目的:探究急性前庭神经炎(VN)患者自发性眼震(SN)强度与前庭功能的相关性,明确半规管功能受损程度与SN特征之间的量化关系。方法:251例急性VN住院患者,入院后均进行眩晕障碍量表(DHI)评估,接受眼震电图、速度阶跃试验(常被称为旋转急停... 目的:探究急性前庭神经炎(VN)患者自发性眼震(SN)强度与前庭功能的相关性,明确半规管功能受损程度与SN特征之间的量化关系。方法:251例急性VN住院患者,入院后均进行眩晕障碍量表(DHI)评估,接受眼震电图、速度阶跃试验(常被称为旋转急停试验)、视频头脉冲试验(v-HIT)检查,按照SN强度分为0~5°、5~15°、>15°三组,分析三组急性VN患者DHI分数、旋转急停试验CP值的差异;分析急性VN患者半规管v-HIT增益值异常情况,及三组患者水平半规管、前半规管、后半规管v-HIT增益值的差异。结果:纳入251例急性VN患者,其中0~5°组51例(20.32%)、5~15°组132例(52.59%)、>15°组68例(27.09%)。急性VN患者DHI分数及CP值均随着SN强度增加而升高,且三组间两两比较差异均有统计学意义(P<0.05)。251例急性VN患者的前庭功能检查中水平半规管v-HIT异常214例(85.26%),前半规管v-HIT异常99例(39.44%),后半规管v-HIT异常69例(27.49%),三组异常率有统计学差异(P<0.05)。急性VN患者水平半规管和前半规患侧增益较健侧下降明显(P<0.05),而后半规患侧增益较健侧差异无统计学意义(P>0.05)。三组间急性VN患者水平、前、后半规管增益在患侧与健侧比较中差异均无统计学意义(P>0.05)。结论:急性VN中SN强度可作为评估前庭系统整体受累程度(包括外周损伤范围与中枢代偿状态)的综合指标,其机制可能与前庭神经广泛受累或中枢代偿调节异常相关,而非单纯由半规管解剖损伤程度决定。 展开更多
关键词 前庭神经炎 自发性眼震 旋转试验 视频头脉冲试验 眩晕障碍量表
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硅酸钠-钠基蒙脱土对砂土工程特性试验研究
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作者 王一名 肖桂元 +2 位作者 代琳 梁河婧 潘嘉圆 《兰州工业学院学报》 2026年第1期88-93,共6页
为探究工程应用中硅酸钠-钠基蒙脱土复合改良砂土的效果,将质量比为0.0%、1.0%、2.0%、3.0%、4.0%的硅酸钠和0.0%、2.0%、4.0%、6.0%的钠基蒙脱土掺入砂土内,通过无侧限抗压强度试验、直剪试验、变水头渗透试验,研究改良砂土的强度特性... 为探究工程应用中硅酸钠-钠基蒙脱土复合改良砂土的效果,将质量比为0.0%、1.0%、2.0%、3.0%、4.0%的硅酸钠和0.0%、2.0%、4.0%、6.0%的钠基蒙脱土掺入砂土内,通过无侧限抗压强度试验、直剪试验、变水头渗透试验,研究改良砂土的强度特性及渗透特性,并结合SEM微观试验,分析了硅酸钠和钠基蒙脱土在改良砂土中的作用机制,探讨了其对砂土强度和渗透性的改进机理。结果表明:硅酸钠和钠基蒙脱土均能增强砂土的力学强度和降低砂土渗透性,两者复合后土体力学强度达到峰值,其强度最佳配比为硅酸钠2%、钠基蒙脱土4%;渗透性无最佳掺比,硅酸钠会使渗透性缓慢降低,钠基蒙脱土则会使其稳定,二者复合能缩小降低区间,使渗透性趋于稳定。研究结果可为土体加固及抗渗技术的选择和评估提供参考依据。 展开更多
关键词 砂土 硅酸钠 钠基蒙脱土 变水头渗透试验 直接剪切试验
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血管迷走性晕厥患者直立倾斜试验阳性分型的影响因素分析
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作者 郭露燕 包艳苹 +1 位作者 包丽芳 俞剑昀 《心电与循环》 2026年第1期41-45,55,共6页
目的分析血管迷走性晕厥(VVS)患者直立倾斜试验(HUTT)阳性分型的影响因素。方法回顾性选取2023年1月至2024年12月金华市中心医院因不明原因晕厥的患者199例,收集并比较HUTT阳性与阴性、不同HUTT阳性分型患者性别、基础疾病、心电图参数... 目的分析血管迷走性晕厥(VVS)患者直立倾斜试验(HUTT)阳性分型的影响因素。方法回顾性选取2023年1月至2024年12月金华市中心医院因不明原因晕厥的患者199例,收集并比较HUTT阳性与阴性、不同HUTT阳性分型患者性别、基础疾病、心电图参数及血常规参数等临床资料。采用多因素logistic回归分析HUTT阳性及阳性分型的影响因素。结果HUTT阳性组103例,阴性组96例;两组患者性别、体重指数、QT间期、QTc间期以及红细胞比容(HCT)、嗜中性粒细胞计数、白细胞计数(WBC)、血红蛋白、平均红细胞血红蛋白、血小板计数、单核细胞计数、平均血小板体积比较,差异均有统计学意义(均P<0.05);性别(OR=4.549)、QT间期(OR=1.012)、WBC(OR=0.814)均是HUTT阳性的独立影响因素(均P<0.05)。103例阳性患者中,混合型51例,心脏抑制型9例,血管抑制型43例;不同HUTT阳性分型患者性别、年龄、体重指数、高血压患病率、糖尿病患病率、高脂血症患病率、QRS时间、HCT比较,差异均有统计学意义(均P<0.05)。糖尿病(OR=9.367)、高脂血症(OR=7.539)、性别(OR=5.115)均是HUTT阳性分型为血管抑制型(以混合型为参照)的独立影响因素(均P<0.05)。结论HUTT阳性的VVS患者心电图及血常规参数存在明显差异,而合并糖尿病、高脂血症等基础疾病的男性患者更易诱发血管抑制型VVS。 展开更多
关键词 血管迷走性晕厥 直立倾斜试验 心电图 血常规 影响因素
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某自动武器闭锁状态机头应变模拟试验与仿真研究
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作者 苑大威 贾飞 +1 位作者 解广华 徐鹏 《装备环境工程》 2026年第1期33-39,共7页
目的 解决自动武器闭锁过程不可见、开闭锁过程运动剧烈导致闭锁机构的应力应变难以测试的问题,进而掌握闭锁齿工作状态的力学特性。方法 采用仿真与试验相结合的方法,首先进行自动武器闭锁状态模拟试验,获得4个闭锁齿的应变曲线,实现... 目的 解决自动武器闭锁过程不可见、开闭锁过程运动剧烈导致闭锁机构的应力应变难以测试的问题,进而掌握闭锁齿工作状态的力学特性。方法 采用仿真与试验相结合的方法,首先进行自动武器闭锁状态模拟试验,获得4个闭锁齿的应变曲线,实现自动武器闭锁状态下机头闭锁齿侧壁的应变测试,进而通过有限元仿真进行对比,相互验证结果的有效性。结果 C4、C5位置受力工况恶劣,压应变较大,C1、C2位置更接近于齿根部,呈拉应变状态,C3、C5位置未处于闭锁齿扣合位置,应变值接近于0。结论 结合仿真可以更加全面地观测机头所有位置的应力应变,形成虚实结合的仿真设计方法,更好地分析和预测机头设计中存在的不足,有效避免因强度不足引发失效、断裂等问题,有力支撑自动武器设计。 展开更多
关键词 枪械 机头 应变 仿真 闭锁 模拟试验
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钛合金椭球封头结构极限承载能力及其试验研究
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作者 谢晓忠 胡震 +3 位作者 李艳青 黄如旭 李文跃 刘双 《舰船科学技术》 北大核心 2026年第4期7-11,共5页
针对钛合金椭球封头结构的静强度与承载能力问题,结合理论计算、数值仿真和模型试验3种方法展开研究。设计并研制实物模型1只,基于理论公式与数值计算,获得椭球膜应力和临界失稳压力,进而通过模型试验验证理论和数值方法的适用性。结果... 针对钛合金椭球封头结构的静强度与承载能力问题,结合理论计算、数值仿真和模型试验3种方法展开研究。设计并研制实物模型1只,基于理论公式与数值计算,获得椭球膜应力和临界失稳压力,进而通过模型试验验证理论和数值方法的适用性。结果对比表明,将椭球等效为球壳,并基于球壳理论开展强度和极限承载能力评估的简化处理方法,膜应力的计算结果与数值、试验结果的一致性良好,但临界失稳压力的计算结果偏保守;采用数值方法的直接计算可有效反映椭球结构的应力状态和极限承载能力。研究结论可为椭球结构的设计、计算和评估提供参考依据。 展开更多
关键词 椭球封头 承载能力 理论公式 数值仿真 模型试验
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船用柴油机缸头水套和活塞集中密性检测装置的设计与应用
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作者 赵士鲁 张华东 《中国修船》 2026年第1期48-51,55,共5页
文章介绍了一种用于对解体修理完成后的船用柴油机缸头水套和活塞在车间内集中进行密性检测试验用的装置,分析其设计及应用。该密性检测装置具有低成本、高效率的优势,可解决船用柴油机缸头水套和活塞无法一起进行密性试验的问题。
关键词 船用柴油机 缸头水套 活塞 集中密性检测
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基于无人机平台的图像导引头性能测试方法研究
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作者 王毅 李娜 +2 位作者 李凯 夏显良 厚秉新 《装备环境工程》 2026年第1期25-32,共8页
目的 保证图像导引头性能的可靠性。方法 针对图像导引头的性能测试需求,以无人机为搭载平台,提出一种基于无人机系统的测试方法,主要进行动态性能、环境适应性等测试。通过在半实物仿真实验室对图像导引头的性能测试与实际搭载飞行试... 目的 保证图像导引头性能的可靠性。方法 针对图像导引头的性能测试需求,以无人机为搭载平台,提出一种基于无人机系统的测试方法,主要进行动态性能、环境适应性等测试。通过在半实物仿真实验室对图像导引头的性能测试与实际搭载飞行试验验证作对比的方式,对图像导引头的识别率、跟踪精度、抗干扰等关键性能指标进行量化评估。结果 采用无人机搭载导引头的方式飞行,图像导引头的识别结果与半实物仿真实验室中的结果基本一致,视线角速度测试的结果偏差仅为0.1(°)/s。结论 为了充分验证末制导飞行实验条件下图像导引头的性能指标,开展以无人机为测试平台的新技术、新方法具有深刻意义。 展开更多
关键词 无人机 图像导引头 识别 跟踪 重捕 性能测试
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Deceleration Capacity--A Novel Measure for Autonomic Nervous System in Patients with Vasovagal Syncope on Tilt-table Testing 被引量:9
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作者 黄芬 徐春芳 +5 位作者 邓小燕 左萍 林凡 樊静静 徐文佳 杨晓云 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2017年第3期326-331,共6页
This study was to investigate the changes of autonomic nerve function and hemodynamics in patients with vasovagal syncope(VVS) during head-up tilt-table testing(HUT). HUT was performed in 68 patients with unexplained ... This study was to investigate the changes of autonomic nerve function and hemodynamics in patients with vasovagal syncope(VVS) during head-up tilt-table testing(HUT). HUT was performed in 68 patients with unexplained syncope and 18 healthy subjects served as control group. According to whether bradycardia, hypotension or both took place during the onset of syncope, the patients were divided during the test into three subgroups: vasodepressor syncope(VD), cardioinhibitory syncope(CI) and mixed syncope(MX) subgroups. Heart rate, blood pressure, heart rate variability(HRV), and deceleration capacity(DC) were continuously analyzed during HUT. For all the subjects with positive responses, the normalized low frequency(LFn) and the LF/HF ratio markedly decreased whereas normalized high frequency(HFn) increased when syncope occurred. Syncopal period also caused more significant increase in the power of the DC in positive groups. These changes were more exaggerated compared to controls. All the patients were indicative of a sympathetic surge in the presence of withdrawal vagal activity before syncope and a sympathetic inhibition with a vagal predominance at the syncopal stage by the frequency-domain analysis of HRV. With the measurements of DC, a decreased vagal tone before syncope stage and a vagal activation at the syncopal stage were observed. The vagal tone was higher in subjects showing cardioinhibitory responses at the syncopal stage. DC may provide an alternative method to understand the autonomic profile of VVS patients. 展开更多
关键词 vasovagal syncope deceleration capacity heart rate variability head-up tilt-table testing
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HEAD-US-C对血友病A患者临床分型的评估意义 被引量:3
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作者 张立欣 胡小丽 +2 位作者 赵丽娜 班灵英 陈霞 《贵州医科大学学报》 CAS 2023年第10期1226-1231,共6页
目的探讨我国优化的血友病关节超声评估量表(HEAD-US-C)对血友病A(HA)患者临床分型的评估意义。方法130例HA男性患者根据血浆凝血因子Ⅷ(FⅧ)活性分为轻型(n=39)、中间型(n=31)及重型组(n=60),收集3组患者的临床资料,采用二维超声检查3... 目的探讨我国优化的血友病关节超声评估量表(HEAD-US-C)对血友病A(HA)患者临床分型的评估意义。方法130例HA男性患者根据血浆凝血因子Ⅷ(FⅧ)活性分为轻型(n=39)、中间型(n=31)及重型组(n=60),收集3组患者的临床资料,采用二维超声检查3组患者双侧踝关节、肘关节及膝关节的渗出、纤维隔膜、滑膜厚度、含铁血黄素沉积、软骨改变、骨侵蚀、骨赘及骨重建情况并进行HEAD-US-C评分,采用彩色多普勒超声检查3组患者关节滑膜增厚伴血管增生情况进行HEAD-US-C评分,采用Spearman相关分析HA患者HEAD-US-C各评价指标与总评分及FⅧ因子活性的相关性。结果不同分型HA患者膝关节的滑膜厚度检出率为75.8%、骨软骨改变检出率67.3%、滑膜增厚伴血管增生检出率为69.6%,踝关节滑膜增厚检出率为58.3%;不同分型的HA患者超声评价指标中,膝踝关节滑膜厚度、含铁血黄素沉积、滑膜增厚伴血管增生、膝关节的骨软骨改变及肘关节的含铁血黄素沉积,差异有统计意义(P<0.05);HEAD-US-C各评价指标与总评分呈正相关性,其中检出率较高的滑膜厚度、骨软骨改变及滑膜增厚伴血管增生与总评分的相关性较高(P<0.05);HEAD-US-C各评价指标与FⅧ因子活性呈负相关,其中膝关节的滑膜厚度、骨软骨改变及滑膜增厚伴血管增生与FⅧ因子活性的相关性较高(P<0.05)。结论HEAD-US-C评价指标中滑膜厚度、骨软骨改变及滑膜血管增生对HA患者临床分型的评估意义更大,评分越高,关节破坏越严重。 展开更多
关键词 血友病A 相关性 head-US-C评分 检测指标 临床分型 关节破坏
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视频头脉冲技术检测梅尼埃病与前庭神经炎半规管功能障碍的应用研究
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作者 石艳萍 莫江伟 +1 位作者 李瀛 罗颜 《中华耳科学杂志》 北大核心 2025年第3期384-389,共6页
目的 应用视频头脉冲(video head impulse test,vHIT)技术检测梅尼埃病(Meniere’s disease,MD)与前庭神经炎(vestibular neuritis,VN)半规管功能损害的特点。方法 回顾性选取2017年12月至2023年12月就诊于苏州大学附属第二医院耳鼻喉... 目的 应用视频头脉冲(video head impulse test,vHIT)技术检测梅尼埃病(Meniere’s disease,MD)与前庭神经炎(vestibular neuritis,VN)半规管功能损害的特点。方法 回顾性选取2017年12月至2023年12月就诊于苏州大学附属第二医院耳鼻喉科眩晕专科并明确诊断的单侧MD患者116例,VN患者34例,分别进行冷热试验及vHIT检测6个半规管的功能。结果 25.86%单侧MD患者vHIT检查结果异常,VN患者的vHIT结果异常率为94.1%。单侧MD患者患耳水平半规管受累17例,上半规管受累2例,后半规管受累8例。VN患者患耳水平半规管受累32例,上半规管受累16例,后半规管受累18例。结论 vHIT检测MD及VN不同半规管功能的敏感性可能不同,水平半规管敏感性最高,上半规管敏感性最低,同时半规管功能受损加重时vHIT阳性率增高。 展开更多
关键词 梅尼埃病 前庭神经炎 冷热试验 视频头脉冲试验
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