To the editor:The superior semicircular canal dehiscence was first described by Minor et all in 1998 as a condition in which the superior semicircular canal lacks a bony covering and has gained constantly increasing i...To the editor:The superior semicircular canal dehiscence was first described by Minor et all in 1998 as a condition in which the superior semicircular canal lacks a bony covering and has gained constantly increasing interest since its discovery.2 The symptoms are varied but specific what is known as Minor syndrome or‘third mobile window’syndrome,'as patients may experience autophony with abnormally loud sounds like footsteps,chewing,breathing,eye movement,echoing voice,distortion of environmental sounds and pulsatile tinnitus.展开更多
Researching the cooperative operation and functional expansion of multiple minirobot assemblies has the potential to bring about significant advancements in the practical applications of minirobots.In this study,we pr...Researching the cooperative operation and functional expansion of multiple minirobot assemblies has the potential to bring about significant advancements in the practical applications of minirobots.In this study,we present a novel assembly sys-tem comprised of arc-shaped NdFeB magnetic minirobots.These minirobots can be individually utilized as assembly units,allowing for function expansion and comprehensive capability enhancement.We fabricate four Semicircular Arc Magnetic Minirobots(SAMM)arranged in different configurations and analyze their force and motion characteristics.Furthermore,by using this unit as a base,various expansion structures such as latches,petals,and rings can be assembled through reason-able combinations.We define the comprehensive reinforcement interval by comparatively analyzing changes in the unit's motion characteristics and operational capabilities.Precise motion manipulation is employed to verify the rationality of the basic unit structure and the feasibility of the assembly scheme.Our proposed self-assembly scheme for magnetic minirobots exhibits great potential and may be used as a paradigm for future research on expanding the functionality of minirobots.展开更多
Objective:To investigate the efficacy of quick repositioning maneuver for horizontal semicircular canal benign paroxysmal positional vertigo (H-BPPV). Methods:Clinical data of 67 patients with H-BPPV who underwent qu...Objective:To investigate the efficacy of quick repositioning maneuver for horizontal semicircular canal benign paroxysmal positional vertigo (H-BPPV). Methods:Clinical data of 67 patients with H-BPPV who underwent quick repositioning maneuver in our hospital from July 2009 to November 2014 were retrospectively analyzed. The maneuver involved rotating the patient in the axial plane for 180? from the involved side towards contralateral side as quickly as possible. Results:Complete symptom resolution was achieved in 61 patients (91.0%) at one week and in 64 patients (95.5%) at 3 months post-treatment. During the repositioning maneuver process, there were no obvious untoward responses except transient nausea with or without vomiting in a few patients. Conclusion:The results indicate that the quick repositioning maneuver is an easy and effective alternative treatment in the management of H-BPPV. Copyright ? 2015 The Authors. Production & hosting by Elsevier (Singapore) Pte Ltd On behalf of PLA General Hospital Department of Otolaryngology Head and Neck Surgery. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).展开更多
Coastal defenses such as the breakwaters are important structures to maintain the navigation conditions in a harbor.The estimation of their hydrodynamic characteristics is conventionally done using physical models,sub...Coastal defenses such as the breakwaters are important structures to maintain the navigation conditions in a harbor.The estimation of their hydrodynamic characteristics is conventionally done using physical models,subjecting to higher costs and prolonged procedures.Soft computing methods prove to be useful tools,in cases where the data availability from physical models is limited.The present paper employs adaptive neuro-fuzzy inference system(ANFIS)and artificial neural network(ANN)models to the data obtained from physical model studies to develop a novel methodology to predict the reflection coefficient(Kr)of seaside perforated semicircular breakwaters under low wave heights,for which no physical model data is available.The prediction was done using the input parameters viz.,incident wave height(Hi),wave period(T),center-to-center spacing of perforations(S),diameter of perforations(D),radius of semicircular caisson(R),water depth(d),and semicircular breakwater structure height(hs).The study shows the prediction below the available data range of wave heights is possible by ANFIS and ANN models.However,the ANFIS performed better with R^2=0.9775 and the error reduced in comparison with the ANN model with R2=0.9751.Study includes conventional data segregation and prediction using ANN and ANFIS.展开更多
As a simplified structural model, a semicircular frame is used to study the crashworthiness behavior of an aircraft fuselage. The quasi-static large elastic-plastic deformation of a semicircular frame in the process o...As a simplified structural model, a semicircular frame is used to study the crashworthiness behavior of an aircraft fuselage. The quasi-static large elastic-plastic deformation of a semicircular frame in the process of its being pressed against a rigid ground is analyzed. First, based on the linear elastic assumption, the quasi-static large deformation contact process of the frame can be divided into three phases, i.e., point contact, line contact and post-buckling. By means of a shooting method, the relations between the displacement and contact force as well as the distribution of bending moment in the three phases are obtained. Then, by assuming an elastic, perfectly-plastic moment-curvature relationship for the semi-circular frame, the contact process is analyzed in detail to reveal the plastic collapse mechanism, the traveling of plastic hinge and the force-displacement relationship. In order to verify the analysis, a preliminary experiment was conducted, in which two types of half rings with clamped ends were pressed by a rigid plate. In addition, a numerical simulation is also conducted by employing ABAQUS to analyze both rectangular cross-sectional beam and I-beam. Finally, the theoretical predictions are compared with the experimental results and numerical solutions, showing that the elastic-plastic analysis can predict the contact process very well.展开更多
The water flow over a semicircular weir is investigated numerically and experimentally in this paper. The numerical model solves the Reynolds equation for a mean flow field with thek-ε-turbulent model. To trace the m...The water flow over a semicircular weir is investigated numerically and experimentally in this paper. The numerical model solves the Reynolds equation for a mean flow field with thek-ε-turbulent model. To trace the motion of the free surface, the COF method with geometric reconstruction is employed. The velocity of the flow is measured by means of LDV technique. Four types of flow patterns, the position of the separation and reattachment point, the distribution of shear stress on the bed at downstream of the weir are presented and discussed. The numerical results agree well with the experiment data.展开更多
Introduction: Superior semicircular canal dehiscence(SCD) remains difficult to diagnose despite advances in high-resolution computed tomography(HRCT) imaging. We hypothesize possible associations between gross tempora...Introduction: Superior semicircular canal dehiscence(SCD) remains difficult to diagnose despite advances in high-resolution computed tomography(HRCT) imaging. We hypothesize possible associations between gross temporal bone anatomy and sub-millimeter pathology of the semicircular canals, which may supplement imaging and clinical suspicion. This pilot study investigates differences in gross temporal bone anatomic parameters between temporal bones with and without SCD.Methods: Records were reviewed for 18 patients referred to an otology clinic complaining of dizziness with normal caloric stimulation results indicative of non-vestibular findings. Eleven patients had normal temporal bone anatomy while seven had SCD. Three-dimensional reconstruction of every patient's temporal bone anatomy was created from patient-specific computational tomography images. Surface area(SA),volume(V), and SA to V ratios(SA:V) were computed across temporal bone anatomical parameters.Results: SCD temporal bones have significantly smaller V, and larger temporal bone SA. Mean(±SD) V was 21,484 ± 3,921 mm^3 in temporal bones without SCD and 16,343 ± 34,471 mm^3 for those with SCD. Their respective SA were 13,733 ± 1,603 mm^2 and 18,073 ± 3,002 mm^2.Temporal bone airspaces and lateral semicircular canals did not demonstrate significant differences where SCD was and was not present. Plots of MV_(warm)response against computed SCD temporal bone anatomic parameters(SA, V and SA:V) showed moderate to strong correlations:temporal bone SA:V(r= 0.64), temporal bone airspace V(r= 0.60), temporal bone airspace SA(r= 0.55), LSCC SA(r= 0.51), and LSCC-toTM Distance(r= 0.65).Conclusions: This analysis demonstrated that SCD is associated with decreased temporal bone volume and density. The defect in SCD does not appear to influence caloric responses.展开更多
In the present study, the reliability design of semicircular breakwater is based on the verification of the rules defined by standard specifications, where partial coefficients are introduced to ensure safety. The rel...In the present study, the reliability design of semicircular breakwater is based on the verification of the rules defined by standard specifications, where partial coefficients are introduced to ensure safety. The reliability of the semicircular breakwaters has been analyzed by using the Hasofer-Lind method to determine the reliability index of structure that has correlated loads, utilizing the long-term observed wave data at a given place. The relation curve between reliability index and safety factor in the traditional design method, as well as the relationships between reliability index and partial coefficients, have been obtained. This paper proposes values of partial coefficients for the design expression of semicircular breakwaters in the cases of anti-sliding and anti-overturning.展开更多
The damage and fracture behaviors of semicircular bending （SCB） asphalt mixture specimens with different orientation notches are experimentally and numerically investigated. In the numerical simulations, asphalt mix...The damage and fracture behaviors of semicircular bending （SCB） asphalt mixture specimens with different orientation notches are experimentally and numerically investigated. In the numerical simulations, asphalt mixture is modeled as a two-phase material, namely a mix of coarse aggregates and asphalt mastic, and the mechanical behavior of asphalt mastic is charac- terized with the damage constitutive model and the damage-based fracture criterion. Some SCB experiments are performed on the asphalt mixture specimens with different orientation notches to validate the numerical method. Finally, the effects of notch orientation and aggregate distrib- ution on crack path, damage distribution, and the load vs. displacement relation are numerically evaluated.展开更多
Scattering of SH wave from an interface cylindrical elastic inclusion with a semicircular disconnected curve is investigated. The solution of dynamic stress concentration factor is given using the Green＇s function an...Scattering of SH wave from an interface cylindrical elastic inclusion with a semicircular disconnected curve is investigated. The solution of dynamic stress concentration factor is given using the Green＇s function and the method of complex variable functions. First, the space is divided into upper and lower parts along the interface. In the lower half space, a suitable Green＇s function for the problem is constructed. It is an essential solution of the displacement field for an elastic half space with a semi-cylindrical hill of cylindrical elastic inclusion while bearing out-plane harmonic line source load at the horizontal surface. Thus, the semicircular disconnected curve can be constructed when the two parts are bonded and continuous on the interface loading the undetermined anti-plane forces on the horizontal surfaces. Also, the expressions of displacement and stress fields are obtained in this situation. Finally, examples and results of dynamic stress concentration factor are given. Influences of the cylindrical inclusion and the difference parameters of the two mediators are discussed.展开更多
Objective: It remains unknown whether calcium metabolism has any effect on the clinical presentation of superior semicircular canal dehiscence(SSCD). Our aim was to analyse the adjusted calcium and vitamin D levels in...Objective: It remains unknown whether calcium metabolism has any effect on the clinical presentation of superior semicircular canal dehiscence(SSCD). Our aim was to analyse the adjusted calcium and vitamin D levels in SSCD patients compared to a control group.Methods: This was a prospective case-control study performed in a tertiary referral center, university teaching hospital in the UK. It included all new patients with SSCD seen in a dedicated skull base clinic over a 5-year period(2015-2019) compared to a gender and age matched control group. The main outcome of the study was adjusted calcium and Vitamin D levels between the two groups.Results: A total of 31 SSCD patients were recruited with a matched number of control patients. The mean Vitamin D level on the SSCD group was 44.8 nmoL/l(SD: 20.8) compared to 47.5 nmoL/l(SD: 27.4) on the control group(p = 0.702). Mean Adjusted calcium level was 2.34 mmoL/l(SD: 0.7) for SSCD compared to2.41 mmoL/l(SD: 0.11) for controls(p = 0.01), being within normal limits for both the SSCD and the control group.Conclusion: Our study did not identify a link between Vitamin D levels and presence of SSCD. Normal adjusted calcium values were found in both groups. Despite that a statistically significant lower calcium level was found in the SSCD group which could indicate that suboptimal levels of calcium may affect the micro-environment of the otic capsule at the SSC region.展开更多
The bending of the thin elastic semicircular plates, because of its complicated boundary conditions, brings some difficulties for us to obtain its solution. This paper applies the reciprocal theorem to propose a gener...The bending of the thin elastic semicircular plates, because of its complicated boundary conditions, brings some difficulties for us to obtain its solution. This paper applies the reciprocal theorem to propose a general simple convenient method to obtain the transverse deflectional equations of the plates.展开更多
Background and Purpose: Despite the strong body of evidence for vestibular rehabilitation, research is lacking for effective clinical management of patients with superior semicircular canal dehiscence (SSCD) and endol...Background and Purpose: Despite the strong body of evidence for vestibular rehabilitation, research is lacking for effective clinical management of patients with superior semicircular canal dehiscence (SSCD) and endolymphatic hydrops (EH). The purpose of this case report is to describe the effects of physical therapy in the treatment of a patient diagnosed with bilateral SSCD. Case Description: The patient was a 56-year-old woman with a long-standing otologic history involving bilateral SSCD and EH. The patient’s body structure and function impairments include constant headaches, dizziness with head rotation and eye movements, sensitivity to sounds and lights, and instability during gait. Her activity limitations include lower extremity dressing, driving, and playing her flute. Her participation restrictions include taking part in social gatherings, going to church, driving longer than 30 minutes, playing with her dogs, and teaching flute lessons. Interventions: Specific interventions included vestibular habituation and adaptation exercises, balance and gait training, and patient education. Physical therapy services were provided for approximately 11 weeks with a frequency of two times per week. Outcomes: After eleven weeks of physical therapy, the patient made improvements on the Lower Extremity Functional Scale (43/80 to 52/80), the Dynamic Gait Index (19/24 to 24/24), the Dizziness Handicap Inventory (86/100 to 68/100), and the Sharpened Romberg (2 seconds to >30 seconds). The patient improved in all her activity limitations and participation restrictions. She was able to play her flute for 20-minute intervals, play with her dogs, partake in social gatherings, and drive for 5 hours without symptoms. The patient had plans to pursue surgical intervention within the next year. Discussion: For a patient with a complex otologic history and a current diagnosis of bilateral SSCD, vestibular rehabilitation was an effective management option. The information from this case can be used to guide the effective treatment of similar patients diagnosed with vestibular dysfunction.展开更多
Purpose:To construct a symptoms-based prediction tool to assess the likelihood of superior canal dehiscence(SSCD)on high-resolution CT.Materials and methods:Mathematical modeling was employed to predict radiologic evi...Purpose:To construct a symptoms-based prediction tool to assess the likelihood of superior canal dehiscence(SSCD)on high-resolution CT.Materials and methods:Mathematical modeling was employed to predict radiologic evidence of SSCD at a tertiary neurotology referral center.Results:A total of 168 patients were included,of which 118 had imaging-confirmed SSCD.On univariate analysis significant predictors of SSCD presence were:sound/pressure-induced vertigo(p?0.006),disequilibrium(p?0.008),hyperacusis(p?0.008),and autophony(p?0.034).Multivariate analysis enabled a 14-point symptom-weighted tool to be developed,wherein a score of6 raised the suspicion of SSCD(70%likelihood of being present),R2?0.853.Conclusions:The likelihood of SSCD on CT scan can be determined with a high degree of certainty based on symptoms recorded at presentation.Using the evidenced-based diagnostic tool validated herein,a score6 with any symptom combination justifies ordering a CT scan.展开更多
A 73-year-old female presented to the emergency department with chief complaint of dizziness after sustaining a fall one month prior to dizziness onset.Although careful examination of eye movement patterns during posi...A 73-year-old female presented to the emergency department with chief complaint of dizziness after sustaining a fall one month prior to dizziness onset.Although careful examination of eye movement patterns during positional testing was attempted at varying stages of her inpatient admission,her complex nystagmus patterns as a result of traumatic benign paroxysmal vertigo were difficult to manage.In particular,the nystagmus pattern from this case suggests the BPPV was variable and affecting either 1)left posterior semicircular canal(pSCC)exclusively 2)left pSCC and right anterior semicircular canal,3)left and right pSCC canal.This case illustrates the importance of two critical details;positional testing should include observing nystagmus with fixation removed and an experienced clinician should be involved as early as possible.展开更多
Superior semicircular canal dehiscence (SSCD) is a rare entity recently described whose typical clinical symptomatology is represented by dizziness triggered by a variation of pressure. We reported a case of SSCD whic...Superior semicircular canal dehiscence (SSCD) is a rare entity recently described whose typical clinical symptomatology is represented by dizziness triggered by a variation of pressure. We reported a case of SSCD which was diagnosed thanks to computed tomography (CT) scan of the petrous bone conducted systematically in front of mixed deafness with normal eardrum. The SSCD was bilateral and was revealed by mixed deafness on the left side and perception deafness on the right with a normal eardrum without the notion of vertigo. The cervical vestibular evoked myogenic potential (cVEMP) and an ultra-high resolution CT scan of the petrous bones in coronal and sagittal sections allowed the diagnosis. The SSCD should be considered in the presence of any conductive or mixed hearing loss with a normal eardrum. The CT scan in coronal and sagittal submillimetric sections allows the diagnosis.展开更多
We describe three patients with severe disabling symptoms of unilateral dehiscence of the superior semicircular canal (DSSC) who had surgical treatment. Each patient underwent a unilateral subtemporal extradural appro...We describe three patients with severe disabling symptoms of unilateral dehiscence of the superior semicircular canal (DSSC) who had surgical treatment. Each patient underwent a unilateral subtemporal extradural approach with resurfacing the DCCS. In all 3 patients, all symptoms were completely resolved and remained symptom free on the long term. There were no postoperative complications. Only one patient experienced a temporary CSF hypotension syndrome and some dizziness. The pseudo-conductive hearing loss improved or resolved in all patients. Surgical treatment should be considered in patients with severe, disabling DSSC symptoms. Surgical resurfacing of the DSSC is a safe and rewarding surgical technique. The long term success rate regarding the elimination of the pseudo-conductive hearing loss and resolution of vestibular symptoms outweigh the potential surgical risks of this technique in these patients.展开更多
文摘To the editor:The superior semicircular canal dehiscence was first described by Minor et all in 1998 as a condition in which the superior semicircular canal lacks a bony covering and has gained constantly increasing interest since its discovery.2 The symptoms are varied but specific what is known as Minor syndrome or‘third mobile window’syndrome,'as patients may experience autophony with abnormally loud sounds like footsteps,chewing,breathing,eye movement,echoing voice,distortion of environmental sounds and pulsatile tinnitus.
基金financial support through National Natural Science Foundation of China(Project No.62273289)The Youth Innovation Science and Technology Support Program of Shandong Province(Project No.2022KJ274)Graduate Innovation Foundation of Yantai University,GIFYTU.
文摘Researching the cooperative operation and functional expansion of multiple minirobot assemblies has the potential to bring about significant advancements in the practical applications of minirobots.In this study,we present a novel assembly sys-tem comprised of arc-shaped NdFeB magnetic minirobots.These minirobots can be individually utilized as assembly units,allowing for function expansion and comprehensive capability enhancement.We fabricate four Semicircular Arc Magnetic Minirobots(SAMM)arranged in different configurations and analyze their force and motion characteristics.Furthermore,by using this unit as a base,various expansion structures such as latches,petals,and rings can be assembled through reason-able combinations.We define the comprehensive reinforcement interval by comparatively analyzing changes in the unit's motion characteristics and operational capabilities.Precise motion manipulation is employed to verify the rationality of the basic unit structure and the feasibility of the assembly scheme.Our proposed self-assembly scheme for magnetic minirobots exhibits great potential and may be used as a paradigm for future research on expanding the functionality of minirobots.
文摘Objective:To investigate the efficacy of quick repositioning maneuver for horizontal semicircular canal benign paroxysmal positional vertigo (H-BPPV). Methods:Clinical data of 67 patients with H-BPPV who underwent quick repositioning maneuver in our hospital from July 2009 to November 2014 were retrospectively analyzed. The maneuver involved rotating the patient in the axial plane for 180? from the involved side towards contralateral side as quickly as possible. Results:Complete symptom resolution was achieved in 61 patients (91.0%) at one week and in 64 patients (95.5%) at 3 months post-treatment. During the repositioning maneuver process, there were no obvious untoward responses except transient nausea with or without vomiting in a few patients. Conclusion:The results indicate that the quick repositioning maneuver is an easy and effective alternative treatment in the management of H-BPPV. Copyright ? 2015 The Authors. Production & hosting by Elsevier (Singapore) Pte Ltd On behalf of PLA General Hospital Department of Otolaryngology Head and Neck Surgery. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
文摘Coastal defenses such as the breakwaters are important structures to maintain the navigation conditions in a harbor.The estimation of their hydrodynamic characteristics is conventionally done using physical models,subjecting to higher costs and prolonged procedures.Soft computing methods prove to be useful tools,in cases where the data availability from physical models is limited.The present paper employs adaptive neuro-fuzzy inference system(ANFIS)and artificial neural network(ANN)models to the data obtained from physical model studies to develop a novel methodology to predict the reflection coefficient(Kr)of seaside perforated semicircular breakwaters under low wave heights,for which no physical model data is available.The prediction was done using the input parameters viz.,incident wave height(Hi),wave period(T),center-to-center spacing of perforations(S),diameter of perforations(D),radius of semicircular caisson(R),water depth(d),and semicircular breakwater structure height(hs).The study shows the prediction below the available data range of wave heights is possible by ANFIS and ANN models.However,the ANFIS performed better with R^2=0.9775 and the error reduced in comparison with the ANN model with R2=0.9751.Study includes conventional data segregation and prediction using ANN and ANFIS.
基金the National Natural Science Foundation of China (10532020)
文摘As a simplified structural model, a semicircular frame is used to study the crashworthiness behavior of an aircraft fuselage. The quasi-static large elastic-plastic deformation of a semicircular frame in the process of its being pressed against a rigid ground is analyzed. First, based on the linear elastic assumption, the quasi-static large deformation contact process of the frame can be divided into three phases, i.e., point contact, line contact and post-buckling. By means of a shooting method, the relations between the displacement and contact force as well as the distribution of bending moment in the three phases are obtained. Then, by assuming an elastic, perfectly-plastic moment-curvature relationship for the semi-circular frame, the contact process is analyzed in detail to reveal the plastic collapse mechanism, the traveling of plastic hinge and the force-displacement relationship. In order to verify the analysis, a preliminary experiment was conducted, in which two types of half rings with clamped ends were pressed by a rigid plate. In addition, a numerical simulation is also conducted by employing ABAQUS to analyze both rectangular cross-sectional beam and I-beam. Finally, the theoretical predictions are compared with the experimental results and numerical solutions, showing that the elastic-plastic analysis can predict the contact process very well.
文摘The water flow over a semicircular weir is investigated numerically and experimentally in this paper. The numerical model solves the Reynolds equation for a mean flow field with thek-ε-turbulent model. To trace the motion of the free surface, the COF method with geometric reconstruction is employed. The velocity of the flow is measured by means of LDV technique. Four types of flow patterns, the position of the separation and reattachment point, the distribution of shear stress on the bed at downstream of the weir are presented and discussed. The numerical results agree well with the experiment data.
基金supported in part by the National Institutes of Health (United States of America) under Award Numbers 5T32DC013018-03 and TL1TR001116
文摘Introduction: Superior semicircular canal dehiscence(SCD) remains difficult to diagnose despite advances in high-resolution computed tomography(HRCT) imaging. We hypothesize possible associations between gross temporal bone anatomy and sub-millimeter pathology of the semicircular canals, which may supplement imaging and clinical suspicion. This pilot study investigates differences in gross temporal bone anatomic parameters between temporal bones with and without SCD.Methods: Records were reviewed for 18 patients referred to an otology clinic complaining of dizziness with normal caloric stimulation results indicative of non-vestibular findings. Eleven patients had normal temporal bone anatomy while seven had SCD. Three-dimensional reconstruction of every patient's temporal bone anatomy was created from patient-specific computational tomography images. Surface area(SA),volume(V), and SA to V ratios(SA:V) were computed across temporal bone anatomical parameters.Results: SCD temporal bones have significantly smaller V, and larger temporal bone SA. Mean(±SD) V was 21,484 ± 3,921 mm^3 in temporal bones without SCD and 16,343 ± 34,471 mm^3 for those with SCD. Their respective SA were 13,733 ± 1,603 mm^2 and 18,073 ± 3,002 mm^2.Temporal bone airspaces and lateral semicircular canals did not demonstrate significant differences where SCD was and was not present. Plots of MV_(warm)response against computed SCD temporal bone anatomic parameters(SA, V and SA:V) showed moderate to strong correlations:temporal bone SA:V(r= 0.64), temporal bone airspace V(r= 0.60), temporal bone airspace SA(r= 0.55), LSCC SA(r= 0.51), and LSCC-toTM Distance(r= 0.65).Conclusions: This analysis demonstrated that SCD is associated with decreased temporal bone volume and density. The defect in SCD does not appear to influence caloric responses.
基金supported by the BK21 Division for u-CITY Construction,Sungkyunkwan University,Korea
文摘In the present study, the reliability design of semicircular breakwater is based on the verification of the rules defined by standard specifications, where partial coefficients are introduced to ensure safety. The reliability of the semicircular breakwaters has been analyzed by using the Hasofer-Lind method to determine the reliability index of structure that has correlated loads, utilizing the long-term observed wave data at a given place. The relation curve between reliability index and safety factor in the traditional design method, as well as the relationships between reliability index and partial coefficients, have been obtained. This paper proposes values of partial coefficients for the design expression of semicircular breakwaters in the cases of anti-sliding and anti-overturning.
基金supported by the National Natural Science Foundation of China(Nos.10872073 and 11602178)the Hubei Provincial Natural Science Foundation of China(No.2015CFB205)
文摘The damage and fracture behaviors of semicircular bending （SCB） asphalt mixture specimens with different orientation notches are experimentally and numerically investigated. In the numerical simulations, asphalt mixture is modeled as a two-phase material, namely a mix of coarse aggregates and asphalt mastic, and the mechanical behavior of asphalt mastic is charac- terized with the damage constitutive model and the damage-based fracture criterion. Some SCB experiments are performed on the asphalt mixture specimens with different orientation notches to validate the numerical method. Finally, the effects of notch orientation and aggregate distrib- ution on crack path, damage distribution, and the load vs. displacement relation are numerically evaluated.
基金Project supported by the Natural Science Foundation of Heilongjiang Province (No.A0206)
文摘Scattering of SH wave from an interface cylindrical elastic inclusion with a semicircular disconnected curve is investigated. The solution of dynamic stress concentration factor is given using the Green＇s function and the method of complex variable functions. First, the space is divided into upper and lower parts along the interface. In the lower half space, a suitable Green＇s function for the problem is constructed. It is an essential solution of the displacement field for an elastic half space with a semi-cylindrical hill of cylindrical elastic inclusion while bearing out-plane harmonic line source load at the horizontal surface. Thus, the semicircular disconnected curve can be constructed when the two parts are bonded and continuous on the interface loading the undetermined anti-plane forces on the horizontal surfaces. Also, the expressions of displacement and stress fields are obtained in this situation. Finally, examples and results of dynamic stress concentration factor are given. Influences of the cylindrical inclusion and the difference parameters of the two mediators are discussed.
文摘Objective: It remains unknown whether calcium metabolism has any effect on the clinical presentation of superior semicircular canal dehiscence(SSCD). Our aim was to analyse the adjusted calcium and vitamin D levels in SSCD patients compared to a control group.Methods: This was a prospective case-control study performed in a tertiary referral center, university teaching hospital in the UK. It included all new patients with SSCD seen in a dedicated skull base clinic over a 5-year period(2015-2019) compared to a gender and age matched control group. The main outcome of the study was adjusted calcium and Vitamin D levels between the two groups.Results: A total of 31 SSCD patients were recruited with a matched number of control patients. The mean Vitamin D level on the SSCD group was 44.8 nmoL/l(SD: 20.8) compared to 47.5 nmoL/l(SD: 27.4) on the control group(p = 0.702). Mean Adjusted calcium level was 2.34 mmoL/l(SD: 0.7) for SSCD compared to2.41 mmoL/l(SD: 0.11) for controls(p = 0.01), being within normal limits for both the SSCD and the control group.Conclusion: Our study did not identify a link between Vitamin D levels and presence of SSCD. Normal adjusted calcium values were found in both groups. Despite that a statistically significant lower calcium level was found in the SSCD group which could indicate that suboptimal levels of calcium may affect the micro-environment of the otic capsule at the SSC region.
文摘The bending of the thin elastic semicircular plates, because of its complicated boundary conditions, brings some difficulties for us to obtain its solution. This paper applies the reciprocal theorem to propose a general simple convenient method to obtain the transverse deflectional equations of the plates.
文摘Background and Purpose: Despite the strong body of evidence for vestibular rehabilitation, research is lacking for effective clinical management of patients with superior semicircular canal dehiscence (SSCD) and endolymphatic hydrops (EH). The purpose of this case report is to describe the effects of physical therapy in the treatment of a patient diagnosed with bilateral SSCD. Case Description: The patient was a 56-year-old woman with a long-standing otologic history involving bilateral SSCD and EH. The patient’s body structure and function impairments include constant headaches, dizziness with head rotation and eye movements, sensitivity to sounds and lights, and instability during gait. Her activity limitations include lower extremity dressing, driving, and playing her flute. Her participation restrictions include taking part in social gatherings, going to church, driving longer than 30 minutes, playing with her dogs, and teaching flute lessons. Interventions: Specific interventions included vestibular habituation and adaptation exercises, balance and gait training, and patient education. Physical therapy services were provided for approximately 11 weeks with a frequency of two times per week. Outcomes: After eleven weeks of physical therapy, the patient made improvements on the Lower Extremity Functional Scale (43/80 to 52/80), the Dynamic Gait Index (19/24 to 24/24), the Dizziness Handicap Inventory (86/100 to 68/100), and the Sharpened Romberg (2 seconds to >30 seconds). The patient improved in all her activity limitations and participation restrictions. She was able to play her flute for 20-minute intervals, play with her dogs, partake in social gatherings, and drive for 5 hours without symptoms. The patient had plans to pursue surgical intervention within the next year. Discussion: For a patient with a complex otologic history and a current diagnosis of bilateral SSCD, vestibular rehabilitation was an effective management option. The information from this case can be used to guide the effective treatment of similar patients diagnosed with vestibular dysfunction.
文摘Purpose:To construct a symptoms-based prediction tool to assess the likelihood of superior canal dehiscence(SSCD)on high-resolution CT.Materials and methods:Mathematical modeling was employed to predict radiologic evidence of SSCD at a tertiary neurotology referral center.Results:A total of 168 patients were included,of which 118 had imaging-confirmed SSCD.On univariate analysis significant predictors of SSCD presence were:sound/pressure-induced vertigo(p?0.006),disequilibrium(p?0.008),hyperacusis(p?0.008),and autophony(p?0.034).Multivariate analysis enabled a 14-point symptom-weighted tool to be developed,wherein a score of6 raised the suspicion of SSCD(70%likelihood of being present),R2?0.853.Conclusions:The likelihood of SSCD on CT scan can be determined with a high degree of certainty based on symptoms recorded at presentation.Using the evidenced-based diagnostic tool validated herein,a score6 with any symptom combination justifies ordering a CT scan.
文摘A 73-year-old female presented to the emergency department with chief complaint of dizziness after sustaining a fall one month prior to dizziness onset.Although careful examination of eye movement patterns during positional testing was attempted at varying stages of her inpatient admission,her complex nystagmus patterns as a result of traumatic benign paroxysmal vertigo were difficult to manage.In particular,the nystagmus pattern from this case suggests the BPPV was variable and affecting either 1)left posterior semicircular canal(pSCC)exclusively 2)left pSCC and right anterior semicircular canal,3)left and right pSCC canal.This case illustrates the importance of two critical details;positional testing should include observing nystagmus with fixation removed and an experienced clinician should be involved as early as possible.
文摘Superior semicircular canal dehiscence (SSCD) is a rare entity recently described whose typical clinical symptomatology is represented by dizziness triggered by a variation of pressure. We reported a case of SSCD which was diagnosed thanks to computed tomography (CT) scan of the petrous bone conducted systematically in front of mixed deafness with normal eardrum. The SSCD was bilateral and was revealed by mixed deafness on the left side and perception deafness on the right with a normal eardrum without the notion of vertigo. The cervical vestibular evoked myogenic potential (cVEMP) and an ultra-high resolution CT scan of the petrous bones in coronal and sagittal sections allowed the diagnosis. The SSCD should be considered in the presence of any conductive or mixed hearing loss with a normal eardrum. The CT scan in coronal and sagittal submillimetric sections allows the diagnosis.
文摘We describe three patients with severe disabling symptoms of unilateral dehiscence of the superior semicircular canal (DSSC) who had surgical treatment. Each patient underwent a unilateral subtemporal extradural approach with resurfacing the DCCS. In all 3 patients, all symptoms were completely resolved and remained symptom free on the long term. There were no postoperative complications. Only one patient experienced a temporary CSF hypotension syndrome and some dizziness. The pseudo-conductive hearing loss improved or resolved in all patients. Surgical treatment should be considered in patients with severe, disabling DSSC symptoms. Surgical resurfacing of the DSSC is a safe and rewarding surgical technique. The long term success rate regarding the elimination of the pseudo-conductive hearing loss and resolution of vestibular symptoms outweigh the potential surgical risks of this technique in these patients.
