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...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.展开更多
"Rocking chair"type lithium-ion batteries with lithium metal-free anodes have been successfully com-mercialized over the past few decades.Zinc-ion batteries(zIBs)have gained increasing attention in recent ye..."Rocking chair"type lithium-ion batteries with lithium metal-free anodes have been successfully com-mercialized over the past few decades.Zinc-ion batteries(zIBs)have gained increasing attention in recent years given their safety,greenness,ease of manufacture,and cost-efficiency.Nevertheless,the practical application of ZIBs is largely hindered by the dendritic growth of the Zn metal anode,low Coulombic eficiency,great harm,and existence of various side reactions.Herein,this review provides a systematic overview of emerging"rocking chair"type ZIBs with zinc metal-free anodes.Firstly,the basic fundamen-tals,advantages,and challenges of“rocking chair”type ZIBs are introduced.Subsequently,an overview of the design principles and recent progress of"rocking chair"type ZIBs with zinc metal-free anodes are presented.Finally,the key challenges and perspectives for future advancement of"rocking chair"type ZiBs with zinc metal-free anodes are proposed.This review is anticipated to attracted increased focus to metal-free anodes"rocking chair"type metal-ion battery and provide new inspirations for the develop-ment of high-energy metal-ion batteries.展开更多
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 tes...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.展开更多
In this study,a human-chair model was developed as the basis for a wearable-chair design.A prototype chair,HUST-EC,based on the model was fabricated and evaluated.Employing the optimization under the golden divisional...In this study,a human-chair model was developed as the basis for a wearable-chair design.A prototype chair,HUST-EC,based on the model was fabricated and evaluated.Employing the optimization under the golden divisional method,an optimized simulation of the operating mode with the lowest chair height was implemented.A novel multi-link support structure has been established with parameters optimized using Matlab software.The stress analysis of the solid models was conducted to ensure the adequate support from the designed chair for the user.Ten subjects participated in the evaluation experiment,who performed both static tasks and dynamic tasks.The experimental results consisted of subjective evaluation and objective evaluation.The experimental data demonstrate that(1)the HUST-EC can effectively reduce the activation level of related muscles at a variety of tasks;(2)the plantar pressure was reduced by 54%–67%;(3)the angle between the upper body and the vertical axis was reduced by 59%–77%;(4)the subjective scores for chair comfortability,portability,and stability were all higher than 7.The results further revealed that the designed chair can reduce the musculoskeletal burden and may improve work efficiency.展开更多
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...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.展开更多
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 func...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.展开更多
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 ...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.展开更多
For the existing problems of walking chair robot such as simple function,lower bearing capacity and not walking in complex environment,a novel varistructured quadruped / biped human-carrying walking chair robot is pro...For the existing problems of walking chair robot such as simple function,lower bearing capacity and not walking in complex environment,a novel varistructured quadruped / biped human-carrying walking chair robot is proposed.The proposed robot could be used as biped and quadruped walking chair robots.Considering the conversion of the walking chair robot from the quadruped to the biped or vice versa,6-UPS and 2-UPS＋UP（U,P and S are universal joint,the prismatic pair,and sphere joint,respectively） parallel mechanisms are selected as the leg mechanism of the biped walking robot and quadruped walking robot,respectively.Combining the screw theory and theory of mechanism,the degrees of freedom of the leg mechanism and the body mechanism in diferent motion states are computed so as to meet the requirements of mechanism design.The motion characteristics of the 2-UPS＋UP parallel mechanism which is the key part of the walking chair robot are analyzed.Then,the workspace of the moving platform is drawn and the efect of the structural parameters on the workspace volume is studied.Finally,it is found that the volume of the workspace of the moving platform is bigger when the side length ratio and the vertex angle ratio of the fxed platform and the moving platform which are isosceles triangles are close to 1.This study provides a theoretical foundation for the prototype development.展开更多
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...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.展开更多
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 l...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<sup>®</sup> 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.展开更多
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 pha...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.展开更多
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...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.展开更多
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.
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...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展开更多
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 ch...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.展开更多
This paper investigates how the chair-CEO age dissimilarity and CEO power affect the dispersion and change of chair-CEO pay gap from both static and dynamic perspectives.The substantial age dissimilarity between the c...This paper investigates how the chair-CEO age dissimilarity and CEO power affect the dispersion and change of chair-CEO pay gap from both static and dynamic perspectives.The substantial age dissimilarity between the chairman and the CEO gives rise to cognitive conflict,thereby increasing board monitoring for firms with greater monitoring needs.Using data of China s listed firms from 2009 to 2017,we find a significant negative effect of CEO power on pay gap between the chairman and the CEO.In addition,when CEO is a member of the board or compensation committee,the power of CEO has different influences on the compensation,but the cognitive conflicts caused by chair-CEO age dissimilarity always inhibit the CEO s power.Thus,age dissimilarity has become an important complement to the board s regulatory mechanisms.展开更多
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...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-展开更多
基金supported by the National Key R&D Program of China(2021YFF0501102)the National Natural Science Foundation of China(52372308,U2368202,U1934219,52202392,52022010,U22A2046,52172322,and 62271486).
文摘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.
基金supported the National Natural Science Foundation of China(No.62101296)the Natural Science Foundation of Shaanxi Province(Nos.2021JQ-760 and 2021JQ-756).
文摘"Rocking chair"type lithium-ion batteries with lithium metal-free anodes have been successfully com-mercialized over the past few decades.Zinc-ion batteries(zIBs)have gained increasing attention in recent years given their safety,greenness,ease of manufacture,and cost-efficiency.Nevertheless,the practical application of ZIBs is largely hindered by the dendritic growth of the Zn metal anode,low Coulombic eficiency,great harm,and existence of various side reactions.Herein,this review provides a systematic overview of emerging"rocking chair"type ZIBs with zinc metal-free anodes.Firstly,the basic fundamen-tals,advantages,and challenges of“rocking chair”type ZIBs are introduced.Subsequently,an overview of the design principles and recent progress of"rocking chair"type ZIBs with zinc metal-free anodes are presented.Finally,the key challenges and perspectives for future advancement of"rocking chair"type ZiBs with zinc metal-free anodes are proposed.This review is anticipated to attracted increased focus to metal-free anodes"rocking chair"type metal-ion battery and provide new inspirations for the develop-ment of high-energy metal-ion batteries.
文摘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.
基金This work is partially supported by the National Natural Science Foundation of China(NSFC)under grant numbers 51705163the Fundamental Research Funds for the Central Universities(HUST)under grand numbers 2019kfyXKJC003 and 2019JYCXJJ022.
文摘In this study,a human-chair model was developed as the basis for a wearable-chair design.A prototype chair,HUST-EC,based on the model was fabricated and evaluated.Employing the optimization under the golden divisional method,an optimized simulation of the operating mode with the lowest chair height was implemented.A novel multi-link support structure has been established with parameters optimized using Matlab software.The stress analysis of the solid models was conducted to ensure the adequate support from the designed chair for the user.Ten subjects participated in the evaluation experiment,who performed both static tasks and dynamic tasks.The experimental results consisted of subjective evaluation and objective evaluation.The experimental data demonstrate that(1)the HUST-EC can effectively reduce the activation level of related muscles at a variety of tasks;(2)the plantar pressure was reduced by 54%–67%;(3)the angle between the upper body and the vertical axis was reduced by 59%–77%;(4)the subjective scores for chair comfortability,portability,and stability were all higher than 7.The results further revealed that the designed chair can reduce the musculoskeletal burden and may improve work efficiency.
文摘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.
文摘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.
基金supported by the Natural Science Foundation of China (52102312,51672234,and 52072325)the Natural Science Foundation of Hunan Province of China (2021JJ40528)+2 种基金the China Postdoctoral Science Foundation (2020M682581)the Macao Young Scholars Program (AM2021011)the College Student Innovation and Entrepreneurship Training Program (S202210530051)。
文摘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.
基金supported by National Natural Science Foundation of China (No. 61075099) FP7-PEOPLE-2012-IRSES:Marie Curie Action "International Research Staf Exchange Scheme" (No. 318902)
文摘For the existing problems of walking chair robot such as simple function,lower bearing capacity and not walking in complex environment,a novel varistructured quadruped / biped human-carrying walking chair robot is proposed.The proposed robot could be used as biped and quadruped walking chair robots.Considering the conversion of the walking chair robot from the quadruped to the biped or vice versa,6-UPS and 2-UPS＋UP（U,P and S are universal joint,the prismatic pair,and sphere joint,respectively） parallel mechanisms are selected as the leg mechanism of the biped walking robot and quadruped walking robot,respectively.Combining the screw theory and theory of mechanism,the degrees of freedom of the leg mechanism and the body mechanism in diferent motion states are computed so as to meet the requirements of mechanism design.The motion characteristics of the 2-UPS＋UP parallel mechanism which is the key part of the walking chair robot are analyzed.Then,the workspace of the moving platform is drawn and the efect of the structural parameters on the workspace volume is studied.Finally,it is found that the volume of the workspace of the moving platform is bigger when the side length ratio and the vertex angle ratio of the fxed platform and the moving platform which are isosceles triangles are close to 1.This study provides a theoretical foundation for the prototype development.
文摘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.
文摘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<sup>®</sup> 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.
文摘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.
文摘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.
文摘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.
文摘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
基金Supported by the National Natural Science Foundation of China(No.20771073)the Third Project of"211"in Guangdong Province,China.
文摘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.
基金National Social Science Fund of China(No.15BGL063)Philosophy Social Science Foundation in Colleges and Universities in Jiangsu Province,China(No.2017SJB0820)
文摘This paper investigates how the chair-CEO age dissimilarity and CEO power affect the dispersion and change of chair-CEO pay gap from both static and dynamic perspectives.The substantial age dissimilarity between the chairman and the CEO gives rise to cognitive conflict,thereby increasing board monitoring for firms with greater monitoring needs.Using data of China s listed firms from 2009 to 2017,we find a significant negative effect of CEO power on pay gap between the chairman and the CEO.In addition,when CEO is a member of the board or compensation committee,the power of CEO has different influences on the compensation,but the cognitive conflicts caused by chair-CEO age dissimilarity always inhibit the CEO s power.Thus,age dissimilarity has become an important complement to the board s regulatory mechanisms.
文摘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-
