An improved YOLOv7 for the state identification of sliding chairs in railway turnout

The sliding chairs are important components that support the switch rail conversion in the railway turnout.Due to the harsh environmental erosion and the attack from the wheel vibration,the failure rate of the sliding chairs accounts for up to 10%of the total failure number in turnout.However,there is little research carried out in the existing literature to diagnose the deterioration states of the sliding chairs.To fill out this gap,by utilizing the images containing the sliding chairs,we propose an improved You Only Look Once version 7(YOLOv7)to identify the state of the sliding chairs.Specifically,to meet the challenge brought by the small inter-class differences among the sliding chair states,we first integrate the Convolutional Block Attention Module(CBAM)into the YOLOv7 backbone to screen the information conducive to state identification.Then,an extra detector for a small object is customized into the YOLOv7 network in order to detect the small-scale sliding chairs in images.Meanwhile,we revise the localization loss in the objective function as the Efficient Intersection over Union(EIoU)to optimize the design of the aspect ratio,which helps the localization of the sliding chairs.Next,to address the issue caused by the varying scales of the sliding chairs,we employ K-means++to optimize the priori selection of the initial anchor boxes.Finally,based on the images collected from real-world turnouts,the proposed method is verified and the results show that our method outperforms the basic YOLOv7 in the state identification of the sliding chairs with 4%improvements in terms of both mean Average Precision@0.5(mAP@0.5)and F1-score.

Chair Tilings非周期艺术图案的生成

在Chairtilings结构的基础上构造出新的函数来生成彩色非周期图案,其原胞具有丰富的图形结构,为计算机实现非周期拼砌提供了新方法·

不同手术方案对Chair畸形Ⅰ型患者术后临床疗效的观察

目的探讨不同手术方案对Chair畸形Ⅰ型患者术后的临床疗效,为Chair畸形Ⅰ型患者的治疗提供更优越的手术方案。方法选取2015年5月至2018年4月就诊的128例诊断为Chair畸形Ⅰ型的患者,依据随机数字表法患者随机分为2组,每组64例。2组患者给予术前相关检查,其中对照组给予改良后颅窝减压术治疗,研究组给予后颅窝减压术联合硬膜成形术及小脑扁桃体切除术治疗,2组患者随访12个月,评价2组患者的住院时间、短期临床症状改善情况、并发症发生率、脊髓空洞缓解率及肢体感觉障碍缓解率。结果治疗后2组患者的短期临床症状、脊髓空洞缓解率及肢体感觉障碍缓解率均较前明显改善(P<0.05);研究组患者的住院时间、短期临床症状改善情况和并发症发生率均明显优于对照组(P<0.05),2组患者术后1年的肢体感觉障碍缓解率及脊髓空洞缓解率与对照组比较差异无统计学意义(P>0.05)。结论后颅窝减压术联合硬膜成形术及小脑扁桃体切除术与改良后颅窝减压术比较,临床疗效较为显著,可有效改善患者的相关临床症状,减少并发症的发生率,并且有效缩短患者的住院时间,减少患者及其家庭的经济负担,但是两种术式对于患者的肢体感觉障碍的缓解率及脊髓空洞缓解率未见明显异常,说明对于临床症状及体征不同的患者应采取不同的治疗方案,因人而异与个体化的手段相结合。

足部位置和座椅高度对脑瘫儿童坐-站转移下肢运动学和动力学参数的影响

背景:足位和座椅高度是影响“坐-站转移”的重要因素,但目前对“坐-站转移”动作的研究多侧重于健康人群和帕金森患者,痉挛型脑瘫儿童在不同座椅高度和足部位置下执行“坐-站转移”任务中的下肢运动学和动力学特征尚未可知。目的:探究不同足部位置及座椅高度对脑瘫儿童执行“坐-站转移”任务过程中下肢运动学和动力学参数的影响。方法:选择7名痉挛型脑瘫儿童作为研究对象,对其进行6个任务即3种座椅高度(高、中、低凳)×2种足位(前、后足位)的“坐-站转移”动作测试,采集脑瘫儿童在不同足位和座椅高度下“坐-站转移”时的运动学和动力学数据。结果与结论:(1)时间特征结果表明,相较于低凳条件,脑瘫儿童在高凳条件下进行“坐-站转移”任务所需总时间显著减少(P=0.046);(2)动力学结果表明,抬离瞬间,双足后位条件下的膝关节屈曲力矩显著大于双足前位条件(P=0.049);相较于中凳条件,在高凳条件下膝关节屈曲力矩显著减小(P <0.001);(3)结果提示抬高座椅高度和改变足位条件均对痉挛型脑瘫儿童的“坐-站转移”表现有影响,在高凳双足后位条件下儿童使用较小的运动补偿就可以完成坐站动作;同时高座椅可作为痉挛型脑瘫儿童增强“坐-站转移”表现的辅助工具,高凳双足后位条件更有助于脑瘫儿童“坐-站转移”动作的完成。

单纯后颅窝减压术与后颅窝减压硬膜扩大成形术治疗chair畸形的疗效比较

目的分析单纯后颅窝减压术与后颅窝减压硬膜扩大成形术治疗chair畸形的疗效。方法将60例chair畸形患者按照术式的不同分为观察组和对照组各30例,分别采取后颅窝减压硬膜扩大成形术、单纯后颅窝减压术治疗,对比两组患者术后效果。结果观察组总有效率96.7%较对照组总有效率60%高,其症状消失率明显高于对照组,p<0.05;术后未发生脑脊液漏、颅内感染等并发症,恢复良好。结论颅窝减压硬膜扩大成形术治疗chair畸形疗效优于单纯后颅窝减压术,效果更为显著。

Wireless Head Gesture Controlled Robotic Wheel Chair for Physically Disable Persons

A robotic wheelchair is assumed to be capable of doing tasks like navigation, obstacle detection, etc. using sensors and intelligence. The initial part of the work was development of a cap controlled wheelchair to test and verify the gesture operation. Following that, a real time operating wheelchair was developed consisting of mode changing option between joystick control mode and head gesture control mode as per as the user’s requirement. The wheelchair consists of MPU6050 sensor, joystick module, RF module, battery, dc motor, toggle switch and Arduino. The movement of the head is detected by MPU6050 and the signal is transmitted to the microcontroller. Then the signal is processed by controller and motion of wheelchair is enabled for navigation. The wheelchair was capable of moving left, right, forward and backward direction. The speed of the wheelchair was 4.8 km/h when tested. Design objective of the wheelchair included cost effectiveness without compromising safety, flexibility and mobility for the users.

The Cardiac Function in the Beach Chair Position under General Anesthesia

Background: Shoulder surgery is performed in the beach chair position (BCP). The systemic arterial blood pressure (BP) must be increased to prevent cerebral hypoperfusion. However, it is not clear how the cardiac function is affected when BP increase to maintain cerebral perfusion pressure in anesthetized patients. Methods: An analysis was performed using the data from 13 patients. We prepared a parallel circuit using a FloTrac Sensor transducer and an arterial BP transducer. Following the transfer of the patient to the BCP under general anesthesia, the FloTrac Sensor transducer was placed at the level of the fourth intercostal space, the arterial BP transducer was placed at the external auditory meatus level. We selected two points before surgery (120 s apart), during which the mean arterial BP (mABP) at the level of the brain was stable and at which the values in the supine position and the BCP were within 5 mmHg. Results: While the patients were in the supine position, the mean mABP at the mid-axillary level was 65.7 mmHg. In the BCP, the mean mABP was 66.5 mmHg at the external auditory meatus and 80.7 mmHg at the fourth intercostal space. The cardiac index changed from 2.2 (supine position) to 2.5 l/min/m2 (BCP). The stroke volume index was significantly increased from 35.8 to 42.3 ml/m2 (P = 0.003). The heart rate changed from 63.0 to 58.6 beats/min. The stroke volume variation was significantly decreased from 12.4% to 8.8% (P = 0.024). Conclusion: In order to ensure patient safety, close attention should be paid to the systemic cardiovascular changes that occur when the BP is increased.

Aging effect and test-retest reliability of the sinusoidal harmonic acceleration test and velocity step test using nanotorque rotatory chair

Introduction:Rotatory chair testing has been used to evaluate horizontal canal function.Frequently used tests include sinusoidal harmonic acceleration test(SHAT)and velocity step test(VST).Objectives:Assessment of age effect on the SHAT and VST and assessment of test-retest reliability of the parameters of those two tests.Methods:A prospective study was performed on 100 subjects with no ear or vestibular complaints and normal vestibular evaluation.They were divided into two groups;Group A:below 50 years of age and Group B:50 years of age or above.SHAT was presented at frequencies 0.02,0.04,0.08,0.16,0.32,0.64 Hz with a peak velocity of 60°/s.VST was performed using a maximum velocity of 100°/s with acceleration and deceleration of 200°/s2.Thirty subjects were tested twice to assess reliability.Results:Study participants ranged in age from 20 to 67 years.Regarding group A,the mean age was30.92±7.31 and 55.36±4.61 for group B.No significant differences were found in SHAT parameters between the two groups.As well,there was no significant difference in VST per-rotatory time constant,however,post-rotatory time constant was significantly longer for Group B(P value<0.05).Intraclass correlation coefficient(ICC)values showed moderate to good reliability(ICC 0.5800.818)for SHAT parameters for the lower frequencies and indicated moderate reliability for VST time constant(ICC 0.5090.652).Conclusions:Age has no significant effect on the parameters of SHAT and VST.Test-retest reliability is generally good for both tests.

Sn-doped BiOCl nanosheet with synergistic H^(+)/Zn^(2+)co-insertion for“rocking chair”zinc-ion battery

The development of insertion-type anodes is the key to designing“rocking chair”zinc-ion batteries.However,there is rare report on high mass loading anode with high performances.Here,{001}-oriented Bi OCl nanosheets with Sn doping are proposed as a promising insertion-type anode.The designs of cross-linked CNTs conductive network,{001}-oriented nanosheet,and Sn doping significantly enhance ion/electron transport,proved via experimental tests and theoretical calculations(density of states and diffusion barrier).The H^(+)/Zn^(2+)synergistic co-insertion mechanism is proved via ex situ XRD,Raman,XPS,and SEM tests.Accordingly,this optimized electrode delivers a high reversible capacity of 194 m A h g^(-1)at 0.1 A g^(-1)with a voltage of≈0.37 V and an impressive cyclability with 128 m A h g^(-1)over 2500 cycles at 1 A g^(-1).It also shows satisfactory performances at an ultrahigh mass loading of 10 mg cm^(-2).Moreover,the Sn-Bi OCl//MnO_(2)full cell displays a reversible capacity of 85 m A h g^(-1)at 0.2 A g^(-1)during cyclic test.

Design and Structural Analysis of Flexible Wearable Chair Using Finite Element Method

The flexible wearable chair is like a light weight mobile exoskeleton that allows people to sit any-where in any working position. The traditional chair is difficult to move to different working locations due to its large size, heavy weight (~5 - 7 kg) and rigid structure and thus, they are inappropriate for workplaces where enough space is not available. Flexible wearable chair has a gross weight of 3 kg as it utilizes light-weight aluminium alloy members. Unlike the traditional chair, it consists of kinematic pairs which enable taking halts between continuous movements at any working position and thus, it is capable of reducing the risk of the physical musculoskeletal disorder substantially among workers. The objective of this paper is to focus on the mechanical design and finite element analysis (FEA) of the mechanism using ANSYS® software. In the present work, all the parts of the mechanism are designed under static load condition. The results of the analysis indicate that flexible wearable chair satisfies equilibrium and stability criterion and is capable of reducing fatigue during working in an assembly line/factory.

Randomized Trial of the Use of Dexmedetomidine vs. Propofol after Regional Blockade in Shoulder Surgery Patients in Beach Chair Position

Background: Propofol is often the drug of choice for ambulatory orthopedic cases. However, propofol can be associated with apnea or other events requiring airway interventions. Dexmedetomidine (Dex) has the unique pharmacologic profile of providing sedation without respiratory depression. This is particularly relevant in patients with morbid obesity and/or challenging airways. The hypotheses were: 1) Propofol would cause more apnea or require more airway manipulations than dexmedetomidine;2) Propofol would have shorter post anesthesia unit recovery times;and 3) Dexmedetomidine would be associated with more bradycardia and hypotension. Methods: After IRB approval, 50 patients were randomized to receive either propofol or Dex for Total Intravenous anesthesia (TIVA) after interscalene brachial plexus block was performed preoperatively under ultrasound guidance. The main end points that we measured where: airway interventions, intra-operative bradycardia, hypotension, and PACU length of stay. Results: There were more airway interventions in the propofol group compared to the Dex group. Additionally, the Dex group had significantly longer PACU stays. Conclusion: We would recommend that Dex should be preferentially considered for patients predisposed to airway obstruction;however, the standard use of Dex over Propofol needed to reconsider since the use of Dex as the agent for TIVA was associated with longer PACU stays.

Paraplegia by Acute Cervical Disc Herniation after Shoulder Arthroscopic Surgery in Beach-Chair Position

Paraplegia after non-cervical spine surgery under general anesthesia is a rare devastating postoperative complication [1]. A patient with shoulder pain was scheduled for shoulder arthroscopy due to rotator cuff repair. Arthroscopic shoulder surgery was performed with the patient in the beach-chair. Postoperatively, patients complained the weakness of both lower leg and marked numbness and tingling in the both arms. MRI showed a herniated intervertebral disc between C6 and C7 with spinal cord compression. Despite urgent discectomy, the patient remained dysesthesia of both upper extremities for 6 months. The purpose of this report is to introduce our case with a paraplegia observed after arthroscopic shoulder surgery in beach-chair position because of acute cervical herniation.

Chair Professors and Visiting Professors of ＂Chang Jiang Scholars Program＂

In responding to the ongoing development needs of the university, we are seeking to recruit Chair Professors and Visiting Professors of ＂Chang Jiang Scholars Program＂ at home and abroad.

Chair Professors and Visiting Professors of "Chang Jiang Scholars Program"

In responding to the ongoing development needs of the university, we are seeking to recruit Chair Professors and Visiting Professors of ＂Chang Jiang Scholars Program＂ at home and abroad. School of Medicine, Tsinghua University

MMP-8 analysis in gingival crevicular fluid using ELISA and novel chair-side test

AIM: To validate accuracy of a novel chair-side test for matrix metalloproteinase(MMP)-8 as compared to enzyme-linked immunosorbent assay(ELISA) in Periodontal health and disease.METHODS: Gingival crevicular fluid was collected from 150 subjects, Group 1(healthy)- 50 subjects, Group 2(gingivitis)- 50 subjects and Group 3(chronic periodontitis)- 50 subjects. A chair-side test strip was indigenously prepared using polyclonal antibodies(principle of immunochromatography) to detect the MMP-8 levels. The detection accuracy(sensitivity and specificity) of the MMP-8 levels by chair-side test kit were compared with ELISA at baseline and 3 mo after scaling and root planing among the study population.RESULTS: The novel chair side test detected MMP-8 levels in accordance with ELISA which at baseline were higher in Group 2 and Group 3 as compared to controls(P < 0.05), and these enzyme levels decreased after therapy(P < 0.05). The chair-side test could differentiate healthy, gingivitis and periodontitis. The detection accuracy of the chair-side test strip were on par with ELISA(sensitivity 92.9% and specificity of 100%) which were statistically significant(P < 0.05). A desire to arouse interest about periodontal health and maintenance in the Indian population provided a strong rationale for us to develop our chair-side test strips to suit our economy. Moreover, this was the first ever effort to develop and validate a chair-side test strip to detect MMP-8 levels in the Indian population. This test can be used on a large scale in private dental practice for the early detection of disease, tapping the sites at risk for disease, alongside helps in patient education and motivation for maintenance.CONCLUSION: This study shows that the novel chair side test kit detects MMP-8 levels a biomarker of periodontal disease progression accurately making it a good chair side diagnostic tool. Further, it is cost effective and time saving which can make it applicable in private dental practice on a large scale for the early detection of periodontal disease.

The Case of the Broken Chair

Some time ago I discovered that one of the chairs in myfront hall had a broken leg.I didn’t foresee any great difficultyin getting it mended,as there are a whole lot of antique shopsin the Pimlico Road which is three minutes’walk from myflat,so I set forth one morning carrying the chair with me.Iwent into the first shop confidently expecting a friendly recep-

多体位智能轮椅床椅转换装置的运动学仿真分析

介绍了多体位智能轮椅的坐、躺、立、蹲、行5种姿态的转换功能,对床椅转换装置进行简化处理,建立背板机构的运动学模型,利用MATLAB对模型进行计算,得到背板的角速度和角加速度时间的运动曲线。利用ADAMS对优化后的装置模型进行运动学分析,得到改进后床椅转换装置的运动曲线。结果表明:该装置具有较好的运动学性能,在床椅转换过程中背板的最大角加速度达到了16°/s^(2),小于人体所能承受的最大角加速度50°/s^(2)。改进后,床椅平稳转换的时间有所延长,转换过程耗时7.5 s,在0.7~6.9 s内,背板运动趋于加速度接近0的平稳运动,表明推杆速度设计合理。

Comparison of the Effectiveness of TRV Chair and Canalith Repositioning Procedure (CRP) for the Treatment of Benign Paroxysmal Positional Vertigo (BPPV)

The primary goal of this research is to evaluate the efficacy of traditional manual canalith repositioning procedures (CRP) to that of automated multi-axial repositioning chair (TRV). A total of 37 BPPV positive patients were distributed into two groups. The first group consisted of 20 patients, 10 under 50 years old (young group) and 10 over 50 years old (old group), who received TRV chair treatment, whereas the remaining 17 patients, 7 under 50 years old (young group) and 10 over 50 years old (old group) received CRP treatment. The DHI and VAS questionnaires were given to the patients before and after treatment, and the results were compared. The average VAS score for TRV patients was 84.5% (young group) and 77.5% (old group). These patients’ DHI results were as follows: for young patients, 10% had a mild handicap, 80% had a moderate handicap, and 10% had a severe handicap, while for the elderly, 40% had a mild handicap, 40% had a moderate handicap, and 20% had a severe handicap. The results improved significantly after the first treatment session. Old patients had a VAS of 28%, 30% had a mild handicap and only 10% had a moderate handicap. However, only 43% of the young group and 30% of the old group who underwent standard CRP suffered from mild handicap and had a VAS of 20% and 34.3% successively. The third session revealed that all patients in the TRV chair group had no handicap, whereas the CRP patients indicated that they still had a mild handicap. Upon analyzing the results, both treatment methods revealed the same efficacy in treating single canal BPPV. However, TRV chair appeared to be superior to traditional CRP in treating multi-canal BPPV.

Catalytic Oxidative Coupling of 1-Phenyl-1H-tetrazole-5-thiol(HL) and Complex [Cu(I)_6L_6] with a Chair Configuration

Both a persulfide crystal of L-L（1）, the oxidative coupling product of l-phenyl-lH-tetrazole-5-thiol（HL）, and a neutral copper（1） complex of Cu6L6（2） were self-assembled and their crystal architectures were characterized by CCD method. HL was converted into the persulfide L-L（1） over a metalloporphyrin catalyst with enzymatic characters under ambient conditions. Whlie in the crystal architecture of Cu6L6（2）, 6 copper（1） ions were ligated by 6L anions to construct a Cu6 ring, which just resembled the chair configuration of cyclohexane. Notably, both compounds 1 and 2 exhibit strong photoluminescence in solid state.