Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 808
Filtrar
1.
Artículo en Inglés | MEDLINE | ID: mdl-39231168

RESUMEN

The organisms of animals with full spatial motion ability present fine and complex 3D structures, showing reliable adhesion ability to the substrate. As core issues, the design and manufacture of complex morphology are essential in bionic adhesion technology. Specifically, the end-expanded microstructure array of high adhesion under low preload has widespread potential in the nondestructive fixation and handling of fragile objects. In the fabrication of end-expanded microstructures, the design and manufacture of metal molds with good mechanical strength are the key. In this paper, a microfabrication technology for manufacturing nickel molds based on three-dimensional printing and electroplating was proposed. The effect of the electric field inhomogeneity on the electrodeposition morphology was systematically studied. Typical bionic adhesives with expanded ends were obtained by a roll-to-roll hot embossing (R2R-HE) process. The normal adhesion force of the bionic adhesives is 9.5 N/cm2, which is comparable to that of the gecko. The electroplating process assisted by 3D printing provides a new approach for the fabrication of complex bionic morphologies and large-area bionic adhesion structures.

2.
Materials (Basel) ; 17(15)2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-39124460

RESUMEN

In this study, finite element (FE) simulation by the software Abaqus was relied on to investigate the roll forming process of a wheel rim made of an innovative dual-phase steel, i.e., DP590, after flash butt welding (FBW). In the simulation, an FE model was generated, including the design of the dies for flaring, three-roll forming, and expansion, and detailed key processing parameters based on practical production of the selected DP590. Combined with the microstructures and properties of the weld zone (WZ) and heat-affected zones (HAZs) after FBW, the distribution of stress/strain and the change in thickness of the base metal (BM), WZ and HAZs were analyzed, and compared in the important stages of roll forming. Theoretically, the variation in the microstructure and the corresponding stress-strain behaviors of the BM, WZ, and HAZs after FBW have led to the thickness reduction of DP590 that originated from softening behaviors occurring at the region of subcritical HAZs (SCHAZs), and a small amount of tempered martensite has evidently reduced the hardness and strength of the SCHAZ. Meanwhile, the distribution of stress/strain has been influenced to some extent. Further, the study includes the influence of the friction coefficient on the forming quality of the wheel rim to guarantee the simulation accuracy in practical applications. In sum, the dual-phase steel has to be carefully applied to the wheel rim, which needs to experience the processes of FBW and roll forming, focusing on the performance of SCHAZs.

3.
Heliyon ; 10(15): e35259, 2024 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-39161813

RESUMEN

This research investigates the production of Cu-SiCw composites by using gas pressure infiltration method and the production of Al/Cu-SiCw composite by using the cold rolling method. The layers were bonded by three rolling reductions of 40 %, 50 %, and 60 %. The microstructures of composites before and after roll bonding were discussed based on SEM and EBSD images. Less agglomeration of whiskers was seen after higher rolling reductions which indicates better distribution of reinforcement in copper. In addition, no decomposition and reaction were observed in Cu-SiCw. The effect of rolling reductions on hardness, wear behavior, and tensile properties was also investigated. Hardness, yield, and ultimate strengths increased at higher rolling reductions. The yield and ultimate strengths increased from 118 MPa to 227 MPa after a 40 % rolling reduction to 150 MPa and 263 MPa after a 60 % rolling reduction. The measured friction coefficient and mass loss showed better wear resistance of composites at higher rolling reductions because the layers became hardened. The mass loss decreases from 6.46 mg after a 40 % rolling reduction to 5.42 mg after a 60 % rolling reduction. Worn surfaces based on SEM images showed shallower grooves and less remaining debris.

4.
SAGE Open Med Case Rep ; 12: 2050313X241274185, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39165297

RESUMEN

Herein, we present the case of a 17-month-old boy with asplenia, bilaterally absent pulmonary arteries, and bilateral patent ductus arteriosus, who underwent a successful Fontan operation. The central pulmonary artery was created using a pericardial roll, which was initially oversized due to the elevated pressure from the systemic-to-pulmonary shunt. The size of the roll was reduced through the process of pressure reduction by bidirectional Glenn and Fontan operations. This case provides an example of blood source-associated size transition of the pericardial roll used in the pulmonary position. Recognizing this phenomenon is vital for the successful management of this patient group.

5.
Lancet Reg Health Eur ; 45: 101020, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39188858

RESUMEN

Background: Mpox was first reported in France on May 19 and third-generation live Modified Vaccinia Ankara (MVA-BN) vaccination of multiple-partner men who have sex with men (MSM) was recommended as of July 11, 2022. We assessed the impact of vaccination and of sexual behavior adopted during the epidemic period on mpox incidence in the ANRS-174-DOXYVAC trial enrolling MSM on HIV pre-exposure prophylaxis (PrEP) with history of sexually-transmitted infections (STI) in the previous year. Methods: We compared pre-epidemic socio-behavioral characteristics and change in sexual behaviors after the onset of the epidemic of participants with mpox and mpox-free. Then we compared incidence rates of mpox per 1000 person-months (p-m) between May 9-July 10 (before vaccination of MSM, period-1) and July 11-September 20 2022 (after vaccination launch, period-2) and explored factors explaining the period effect using Poisson regression model. Findings: 472 MSM had data before and after May 9, 2022. Twenty percent had received smallpox vaccine during childhood. Mpox occurred in 77/472 participants (incidence 49.3 per 1000 p-m (95% CI 38.9-61.6)). MVA-BN vaccination roll-out was rapid, with 86% (341/398) of eligible participants having received at least one dose by September 20, 2022. Sexual behavior significantly changed before and after May 9, with a decrease in the proportion of mpox-free participants with >10 partners during last 3 months (45% vs 38%, p = 0.0035). Mpox incidence was 67.4 per 1000 p-m (95% CI 51.6-86.6) in period-1, and 24.4 per 1000 p-m (95% CI 13.9-39.6) in period-2, with an incidence rate ratio of 0.36 (95% CI 0.21-0.63). In multivariable Poisson regression model, only MVA-BN vaccination in 2022 remained significantly associated with mpox incidence, with a 99% risk reduction (95% CI 96.6-99.7). Interpretation: In MSM on PrEP enrolled in the ANRS-174-DOXYVAC trial, rapid roll-out of MVA-BN vaccination was associated with a strong reduction in mpox incidence. Funding: ANRS Maladies Infectieuses Emergentes (ANRS/MIE).

6.
Nano Lett ; 24(34): 10650-10655, 2024 Aug 28.
Artículo en Inglés | MEDLINE | ID: mdl-39158094

RESUMEN

In situ characterizations of charge injection dynamics, equilibrated concentration, and electric field distributions shed light on the critical mechanisms of quantum dot light-emitting diodes (QD-LEDs). In this work, we developed electrically excited transient absorption spectroscopy, which can provide the above key information, to investigate the efficiency roll-off of QD-LEDs. We found that the average electron populations per QD are low when QD-LEDs exhibit efficiency roll-off, excluding Auger recombination as the main cause. We also revealed that the weak electrical field inside the QD layer under forward biases has a negligible impact on the efficiency. Interestingly, we found that as the voltage increases the electron concentration in the QD layer saturates at very low levels. When combined with the concomitant efficiency roll-off, we propose electron leakage is the main loss at elevated driving voltages. We further demonstrate that increasing the electron confinement potential with the ZnS shell enables us to efficiently mitigate the efficiency roll-off.

7.
Angle Orthod ; 2024 Jun 17.
Artículo en Inglés | MEDLINE | ID: mdl-39194995

RESUMEN

OBJECTIVES: To compare mandibular incisor compensation relative to Menton (Me) deviation between skeletal Class III patients with roll- and yaw-dominant mandibular asymmetries. MATERIALS AND METHODS: Sixty skeletal Class III patients (21.62 ± 2.69 years) with facial asymmetry were divided into roll- or yaw-dominant asymmetry groups. Mandibular skeletal and incisor measurements were carried out using cone-beam computed tomography data, and values were compared between the two asymmetry groups or between moderate and severe asymmetry subgroups using independent t-test or Mann-Whitney U-test. The relationship between skeletal and dental measurements was assessed using Pearson correlation coefficient. RESULTS: Relative to the mandibular midsagittal plane, the yaw-dominant group presented significantly greater mandibular dental midline deviation in distance (LI-mid deviation, 2.15 mm) and angulation (4.20°) toward the nondeviated side than the roll-dominant group (P < .001). The ratio of amount of LI-mid deviation to Me deviation was significantly greater in the yaw-dominant group (26.44%) than in the roll-dominant group (1.76%; P < .001). In the yaw-dominant group, the LI-mid deviation was significantly greater in the severe asymmetry subgroup than in the moderate asymmetry subgroup, and the amount of mandibular incisor compensation was positively correlated with Me deviation and mandibular yaw. CONCLUSIONS: Mandibular incisor compensation differed significantly between the roll- and yaw-dominant asymmetry groups. The yaw-dominant group demonstrated significant mandibular dental midline deviation, and dental compensation of the anterior teeth was positively correlated with Me deviation and mandibular yaw.

8.
Materials (Basel) ; 17(16)2024 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-39203155

RESUMEN

Photocurable hybrid organic-inorganic composites were prepared via surface modification and 3D-patterned structures were fabricated by utilizing a continuous roll-to-roll manufacturing strategy. The surfaces of nanocrystals were engineered with a bifunctional ligand that is a 2-carboxyethyl acrylate, which possesses a carboxylic acid moiety at one end and an acrylate functionality moiety at the other end, yielding acrylate-functionalized nanocrystals. Micro-scale 3D patterns (protruding pyramidal shapes with each side measuring 147 µm) were continuously manufactured at a speed of 2.5 m/min via UV curing with a soft engraved mold. The surface properties of the functionalized nanocrystals and their UV curing condition were explored with Fourier transform infrared spectroscopy. The morphology of the 3D film was measured using scanning electron microscopy. A pin-on-disk tribometer measurement revealed an improved interaction between the functionalized particles and resins.

9.
Sci Rep ; 14(1): 19709, 2024 Aug 24.
Artículo en Inglés | MEDLINE | ID: mdl-39181970

RESUMEN

This article demonstrates a mathematical model and theoretical analysis of the Micropolar fluid in the reverse roll coating process. It is important because micropolar fluids account for the microstructure and microrotation of particles within the fluid. These characteristics are significant for accurately describing the behavior of complex fluids such as polymer solutions, biological fluids, and colloidal suspensions. First, we modeled the flow equations using basic laws of fluid dynamics. The flow equations are made modified using low Reynolds number theory. The simplified equations are solved analytically. The exact expression for velocity and pressure gradient are obtained, while pressure is calculated numerically using Simpson Rule. Graphical depictions are carried out to comprehend the impact of the newly emerged physical constraints. The influence of micropolar and microrotation parameters on the velocity, pressure and pressure gradient are elaborated with the help of different graphs.

10.
J Oral Implantol ; 2024 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-38979575

RESUMEN

AIMS: In the present case series, we performed implant surgery using a modified roll envelope technique and an apically repositioned flap (MRARF). To improve patients' peri-implant soft tissue phenotypes, they underwent dental implantation following the buccal contour concavities, inadequate keratinized tissue width, and soft tissue thickness simultaneously. MATERIALS AND METHODS: This case series includes four patients treated between July 2021 and February 2022 who received dental implants and GBR treatment six months earlier and were to be taken up for second-stage surgery. They were eligible for the MRARF technique if each implant site showed a labial and buccal deficiency and a reduced keratinized mucosa width than the adjacent teeth. Sutures were removed two weeks after surgery, and a provisional restoration was delivered. A final impression was taken at six weeks to produce the definitive implant-supported restoration. RESULTS: All surgery sites healed uneventfully, and no postoperative pain or excessive swelling was reported. The modified flap design allowed for increasing the width and thickness of keratinized mucosa with a minimally invasive technique. A harmonious color, texture, and mucogingival junction position that matched the surrounding tissue and adjacent teeth was achieved, and all patients were satisfied with the final results. CONCLUSIONS: MRARF at second-stage implant surgery could obtain satisfactory results regarding vertical and horizontal aesthetic gingival contours and an adequate width and thickness of keratinized mucosa around the implants.

11.
Materials (Basel) ; 17(13)2024 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-38998209

RESUMEN

Cold bending forming is a complex forming process, and its product quality is closely related to the forming process parameters. To mitigate issues such as bulging and waviness arising from the extension of the material at the edges during the forming process of thin-walled circular tubes, a comprehensive comparative analysis was conducted on four forming methods. This analysis determined that the combined bending method is the optimal forming technique for the equipment. For the impact of different parameters on the equivalent plastic strain distribution of the product and the force on the rollers, numerical simulations were carried out using the software COPRA (COPRA FEA RF 2023.1) after designing the pattern diagram based on the integrated bending method. The results showed that different processing speeds on the equivalent plastic strain distribution and work hardening of the plate have little effect. As the spacing between the upper and lower rollers increases, the equivalent plastic strain of the plate to a certain extent and the value of the moment of the rollers is significantly reduced. Analyzing the performance characteristics of high-strength steel materials from the aspects of the thickness strain and cross-sectional forming of the plate, this verifies the advantages of forming high-strength steel plates. The numerical simulation results of this study are in good agreement with actual production experimental results.

12.
Materials (Basel) ; 17(13)2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38998314

RESUMEN

The increase in exploitation durability of two-layer cast rolls with the working layer made of high chromium cast iron allows one to significantly improve the quality of rolled metal as well as to increase the economic efficiency of the manufacturing process. However, it is severely hindered due to the massiveness of castings, the impossibility of both evaluating mechanical properties along the depth of the working layer, and providing the structural uniformity of the working surface and the decrease in stresses. In our research, aiming to enhance the exploitation durability of sheet rolls, it is recommended to achieve structural uniformity by CuMg alloying, which increases the concentration of copper up to 2.78 wt.% in certain zones and, owing to the accelerated austenite decomposition at a high temperature during the cool-down of the castings, led to the reduction in excessive strength and the level of heat stresses in the castings. We propose the regimes of cyclic heat treatments which, due to the decomposition of retained austenite and the fragmentation of structure, control the level of hardness to reduce and uniformize the level of stresses along the length of a barrel. A further improvement in the predictions of exploitation durability using XGboost method, which was performed based on the chemical composition of the working layer of high-chromium cast iron and heat treatment parameters, requires taking into account the factors characterizing exploitation conditions of specific rolling mills and the transformations of structural-phase state of the surface obtained by a non-destructive control method. As the controlled parameter, the hardness measured on the roll's surface is recommended, while the gradient change in mechanical properties along the working layer depth can be feasibly analyzed by a magnetic method of coercive force measuring.

13.
Chem Asian J ; : e202400679, 2024 Jul 29.
Artículo en Inglés | MEDLINE | ID: mdl-39073242

RESUMEN

Despite the rapid development of thermally activated delayed fluorescent (TADF) materials, developing organic light-emitting diodes (OLEDs) with small efficiency roll-off remains a formidable challenge. Herein, we have designed a TADF molecule (mClSFO) based on the spiro fluorene skeleton. The highly twisted structure and multiple charge-transfer channels effectively suppress aggregation-caused quenching (ACQ) and endow mClSFO with excellent exciton dynamic properties to reduce efficiency roll-off. Fast radiative rate (kr) and rapid reverse intersystem crossing (RISC) rate (kRISC) of 1.6 × 107 s-1 and 1.07 × 106 s-1, respectively, are obtained in mClSFO. As a result, OLEDs based on mClSFO obtain impressive maximum external quantum efficiency (EQEmax) exceeding 20% across a wide doping concentration range of 10-60 wt%. 30 wt% doped OLED exhibits an EQEmax of 23.1% with a small efficiency roll-off, maintaining an EQE of 18.6% at 1000 cd m-2. The small efficiency roll-off and low concentration dependence observed in the TADF emitter underscore its significant potential.

14.
World J Surg Oncol ; 22(1): 178, 2024 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-38971793

RESUMEN

BACKGROUND: Any advantage of performing targeted axillary dissection (TAD) compared to sentinel lymph node (SLN) biopsy (SLNB) is under debate in clinically node-positive (cN+) patients diagnosed with breast cancer. Our objective was to assess the feasibility of the removal of the clipped node (RCN) with TAD or without imaging-guided localisation by SLNB to reduce the residual axillary disease in completion axillary lymph node dissection (cALND) in cN+ breast cancer. METHODS: A combined analysis of two prospective cohorts, including 253 patients who underwent SLNB with/without TAD and with/without ALND following NAC, was performed. Finally, 222 patients (cT1-3N1/ycN0M0) with a clipped lymph node that was radiologically visible were analyzed. RESULTS: Overall, the clipped node was successfully identified in 246 patients (97.2%) by imaging. Of 222 patients, the clipped lymph nodes were non-SLNs in 44 patients (19.8%). Of patients in cohort B (n=129) with TAD, the clipped node was successfully removed by preoperative image-guided localisation, or the clipped lymph node was removed as the SLN as detected on preoperative SPECT-CT. Among patients with ypSLN(+) (n=109), no significant difference was found in non-SLN positivity at cALND between patients with TAD and RCN (41.7% vs. 46.9%, p=0.581). In the subgroup with TAD with axillary lymph node dissection (ALND; n=60), however, patients with a lymph node (LN) ratio (LNR) less than 50% and one metastatic LN in the TAD specimen were found to have significantly decreased non-SLN positivity compared to others (27.6% vs. 54.8%, p=0.032, and 22.2% vs. 50%, p=0.046). CONCLUSIONS: TAD by imaging-guided localisation is feasible with excellent identification rates of the clipped node. This approach has also been found to reduce the additional non-SLN positivity rate to encourage omitting ALND in patients with a low metastatic burden undergoing TAD.


Asunto(s)
Axila , Neoplasias de la Mama , Escisión del Ganglio Linfático , Terapia Neoadyuvante , Neoplasia Residual , Biopsia del Ganglio Linfático Centinela , Humanos , Femenino , Neoplasias de la Mama/patología , Neoplasias de la Mama/cirugía , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/diagnóstico por imagen , Escisión del Ganglio Linfático/métodos , Persona de Mediana Edad , Terapia Neoadyuvante/métodos , Estudios Prospectivos , Adulto , Biopsia del Ganglio Linfático Centinela/métodos , Anciano , Neoplasia Residual/cirugía , Neoplasia Residual/patología , Ganglios Linfáticos/patología , Ganglios Linfáticos/cirugía , Ganglios Linfáticos/diagnóstico por imagen , Estudios de Seguimiento , Pronóstico , Metástasis Linfática , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Estudios de Factibilidad
15.
J Orthop Surg Res ; 19(1): 419, 2024 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-39033130

RESUMEN

BACKGROUND: Fundamental morphologic differences between male and female pelvises are historically recognised. Despite this, little consideration has been given as to whether or not conventional positioning supports used for primary total hip arthroplasties (THAs) performed in the lateral position do an equally effective job of maintaining the intended set up position when comparing genders. Given that recent research has highlighted that unintended pelvic roll occurs commonly during hip surgery, and that such movement may have a mechanically-deleterious consequence upon final construct performance and complication rates, this study was undertaken to explore the differences in pelvic roll between genders. METHODS: The output of a high-precision, commercially-available, imageless intra-operative navigation system was prospectively-collected for 85 consecutive patients undergoing unilateral, primary THAs. These data were separated by gender and were utilised to determine differences in pelvic movement around a central sagittal axis. RESULTS: Demographic data were similar between genders, with no between-group differences in mean BMI (p = 0.09) or indication for surgery (p = 0.66), however participating males (mean 68.04) were slightly younger than females (mean 73.31). The mean anterior pelvic roll for females was 9.50°, and for males 8.68°. There were no statistically significant independent correlations observed between gender (p = 0.21) and pelvic roll. CONCLUSION: The findings of this novel study do not suggest gender differences in the magnitude of unintended, intra-operative, anterior roll, even when corrected for BMI and surgical indication. Average roll of ~ 9° was demonstrated across both groups. An awareness of such positional change during THA surgery may reduce potentially-avoidable post-operative complications.


Asunto(s)
Artroplastia de Reemplazo de Cadera , Posicionamiento del Paciente , Humanos , Masculino , Femenino , Artroplastia de Reemplazo de Cadera/métodos , Artroplastia de Reemplazo de Cadera/efectos adversos , Anciano , Persona de Mediana Edad , Posicionamiento del Paciente/métodos , Estudios Prospectivos , Caracteres Sexuales , Anciano de 80 o más Años , Factores Sexuales , Huesos Pélvicos/cirugía , Pelvis/cirugía
16.
Infect Dis Model ; 9(4): 1057-1080, 2024 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38988830

RESUMEN

As the world becomes ever more connected, the chance of pandemics increases as well. The recent COVID-19 pandemic and the concurrent global mass vaccine roll-out provides an ideal setting to learn from and refine our understanding of infectious disease models for better future preparedness. In this review, we systematically analyze and categorize mathematical models that have been developed to design optimal vaccine prioritization strategies of an initially limited vaccine. As older individuals are disproportionately affected by COVID-19, the focus is on models that take age explicitly into account. The lower mobility and activity level of older individuals gives rise to non-trivial trade-offs. Secondary research questions concern the optimal time interval between vaccine doses and spatial vaccine distribution. This review showcases the effect of various modeling assumptions on model outcomes. A solid understanding of these relationships yields better infectious disease models and thus public health decisions during the next pandemic.

17.
Audiol Res ; 14(4): 602-610, 2024 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-39051195

RESUMEN

Sensing gravity through the otolith receptors is crucial for bipedal stability and gait. The overall contribution of the otolith organs to eye movements, postural control, and perceptual functions is the basis for clinical testing of otolith function. With such a wide range of contributions, it is important to recognize that the functional outcomes of these tests may vary depending on the specific method employed to stimulate the hair cells. In this article, we review common methods used for clinical evaluation of otolith function and discuss how different aspects of physiology may affect the functional measurements in these tests. We compare the properties and performance of various clinical tests with an emphasis on the newly developed video ocular counter roll (vOCR), measurement of ocular torsion on fundus photography, and subjective visual vertical or horizontal (SVV/SVH) testing.

18.
Vision (Basel) ; 8(3)2024 Jun 23.
Artículo en Inglés | MEDLINE | ID: mdl-39051226

RESUMEN

This study aims to explore the potential of a novel EYE ROLL device designed to facilitate guided vision relaxation exercises in an open space. A prospective study was performed on 89 participants who perform screenwork for at least four hours daily. All participants were randomly divided into three groups: a Control group with no exercising, a Manual group undertook manual vision relax ation exercises, and an Eyeroll group engaged in EYE ROLL device-assisted vision relaxation exercises. Each participant underwent three evaluations (an initial baseline assessment, a 4-week follow-up, and an 8-week follow-up) with four assessment tools: a comprehensive vision examination, an in-depth questionnaire, saccadic eye movement recordings, and objective accommodation measurements. There was a statistically significant decrease (35% and above) in complaint scores at the 4-week follow-up in both training groups. Although statistically insignificant, complaints continued to decrease after an 8-week period. No significant changes were observed in clinical or objective accommodative parameters. Some variation of visual functions was observed in all groups due to repeated measures. Vision relaxation exercises combined with proper vision ergonomics and working habits can reduce asthenopic complaints. The EYE ROLL device presents a promising tool for integrating these exercises into the working environment.

19.
Front Neurol ; 15: 1432608, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38962475

RESUMEN

Purpose: To evaluate the utility of supine roll test (SRT) and alternative positional tests, such as head-shaking test (HST), seated supine positioning test (SSPT), bow and lean test (BLT), and rapid axial roll test (RART) in determining the affected semicircular canal of horizontal semicircular canal benign paroxysmal positional vertigo (HSC-BPPV). Methods: In an observational cohort study, 553 patients diagnosed with HSC-BPPV were divided into five groups in terms of different positional tests received: SRT group (n = 110), HST+ SRT (n = 112), BLT + SRT (n = 114), SSPT+SRT (n = 108) and RART+SRT (n = 109). The same method was used for the last four groups: The patients were first subjected to different alternative positional tests and then to SRT, and the nystagmus was observed separately to determine the affected side. The primary outcomes compared included the accuracy and sensitivity of these tests in the determination of the affected semicircular canal in HSC-BPPV. Results: Patients with nystagmus elicited by positional tests accounted for 84.99% (470/553). The elicitation rate of nystagmus of SRT was lowest, being 77.27% (85/110). The elicitation rate of nystagmus were higher in the test groups than in the control group, and RART+SRT group yielded the highest elicitation rate of nystagmus (95.41%, 104/109). Among the alternative positional tests, RART attained the highest elicitation rate of nystagmus (101/109, 92.66%). Comparison between alternative positional tests and SRT, RART and SRT showed obviously better agreement in determining the affected semicircular canal (85.45%, 96/109) and eliciting nystagmus (95.41%, Kappa = 0.642), but no difference was found in curative effect when the affected side was accurately determined (χ2 = 1.618, p = 0.655). Conclusion: All alternative positional tests are helpful for eliciting nystagmus in patients with HSC-BPPV, and the significant advantages of RART include high-sensitivity in eliciting nystagmus and high accuracy in determining the affected semicircular canal, which provided objective support for the correct diagnosis of HSC-BPPV and the successful reduction of otolith.

20.
Front Bioeng Biotechnol ; 12: 1336520, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39011154

RESUMEN

People with unilateral transtibial amputation (TTA) using a passive-elastic prosthesis exhibit lower positive affected leg trailing work (ALtrail Wpos) and a greater magnitude of negative unaffected leg leading work (ULlead Wneg) during walking than non-amputees, which may increase joint pain and osteoarthritis risk in the unaffected leg. People with TTA using a stance-phase powered prosthesis (e.g., BiOM, Ottobock, Duderstadt, Germany) walk with increased ALtrail Wpos and potentially decreased magnitude of ULlead Wneg compared to a passive-elastic prosthesis. The BiOM includes a passive-elastic prosthesis with a manufacturer-recommended stiffness category and can be tuned to different power settings, which may change ALtrail Wpos, ULlead Wneg, and the prosthesis effective foot length ratio (EFLR). Thirteen people with TTA walked using 16 different prosthetic stiffness category and power settings on a level treadmill at 0.75-1.75 m/s. We constructed linear mixed effects models to determine the effects of stiffness category and power settings on ALtrail Wpos, ULlead Wneg, and EFLR and hypothesized that decreased stiffness and increased power would increase ALtrail Wpos, not change and decrease ULlead Wneg magnitude, and decrease and not change prosthesis EFLR, respectively. We found there was no significant effect of stiffness category on ALtrail Wpos but increased stiffness reduced ULlead Wneg magnitude, perhaps due to a 0.02 increase in prosthesis EFLR compared to the least stiff category. Furthermore, we found that use of the BiOM with 10% and 20% greater than recommended power increased ALtrail Wpos and decreased ULlead Wneg magnitude at 0.75-1.00 m/s. However, prosthetic power setting depended on walking speed so that use of the BiOM increased ULlead Wneg magnitude at 1.50-1.75 m/s compared to a passive-elastic prosthesis. Ultimately, our results suggest that at 0.75-1.00 m/s, prosthetists should utilize the BiOM attached to a passive-elastic prosthesis with an increased stiffness category and power settings up to 20% greater than recommended based on biological ankle values. This prosthetic configuration can allow people with unilateral transtibial amputation to increase ALtrail Wpos and minimize ULlead Wneg magnitude, which could reduce joint pain and osteoarthritis risk in the unaffected leg and potentially lower the metabolic cost of walking.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA