maximal pressure
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2021 ◽  
Author(s):  
Maria Ruiz-Ramos ◽  
Ángel Manuel Orejana-García ◽  
Ignacio Vives-Merino ◽  
Carmen Bravo-Llatas ◽  
José Luis Lázaro-Martínez ◽  
...  

Abstract Background: Metatarsalgia is a common foot condition. The metatarsophalangeal stabilizing taping technique described by Yu et al. has shown good clinical results as a provisional treatment in propulsive metatarsalgia. 35 The Fixtoe Device®, a novel orthopedic device, intends to simulate stabilizing tape. However, to date, there is no evidence of its effectiveness.Methods: The aim of this study was to assess plantar pressure changes using the Fixtoe Device®, in comparison with the traditional method (stabilizing tape) in a young, healthy sample thorough a cross-sectional study. Maximal pressure (Kpa) and pressure-time integral (Kpa/s) in the second metatarsal head were measured in twenty-four healthy volunteers. Registers were taken in four different conditions: barefoot, traditional stabilizing tape, Fixtoe Device® without metatarsal pad, and Fixtoe Device® with metatarsal pad. Results: Mean second metatarsal head maximal pressure and mean pressure-time integral showed statistical difference among the four analyzed conditions (p < 0.0001 in both cases). The improvement in maximal pressure and pressure-time integral obtained in each intervention also showed significance (p < 0.0001 in both cases). Comparing the improvement of the Fixtoe Device® with and without metatarsal pad with that of tape condition showed a moderate to high and moderate effect size for both peak pressure and pressure-time integral reduction.Conclusions: The Fixtoe Device® reduces median maximal pressure and median pressure-time integral under the second metatarsal head in healthy young individuals. The Fixtoe Device® shows higher effectiveness than the traditional second metatarsophalangeal joint stabilizing taping technique. To our knowledge, this is the first investigation proving the effectiveness of the recently developed Fixtoe Device® in terms of plantar pressure modification, which leads the way to its use in clinics.


2021 ◽  
pp. 1-11
Author(s):  
Martina Kovari ◽  
Jan Stovicek ◽  
Jakub Novak ◽  
Michaela Havlickova ◽  
Sarka Mala ◽  
...  

BACKGROUND: Anorectal dysfunction (ARD), especially bowel incontinence, frequently compromises the quality of life in multiple sclerosis (MS) patients. The effect of rehabilitation procedures has not been clearly established. OBJECTIVE: To determine the effect of an individualized rehabilitation approach on bowel incontinence and anorectal pressures. METHODS: MS patients with ARD underwent 6-months of individually targeted biofeedback rehabilitation. High resolution anorectal manometry (HRAM) and St. Mark’s Fecal Incontinence Scores (SMIS) were completed prior to rehabilitation, after 10 weeks of supervised physiotherapy, and after 3 months of self-treatment. RESULTS: Ten patients (50%) completed the study. Repeated measures analysis of variance (ANOVA) demonstrated significant improvement in the SMIS questionnaire over time [14.00 baseline vs. 9.70 after supervised physiotherapy vs. 9.30 after self-treatment (p = 0.005)]. No significant improvements over time were noted in any HRAM readings: maximal pressure [49.85 mmHg baseline vs. 57.60 after supervised physiotherapy vs. 60.88 after self-treatment (p = 0.58)], pressure endurance [36.41 vs. 46.89 vs. 49.95 (p = 0.53)], resting pressure [55.83, vs 52.69 vs. 51.84 (p = 0.704)], or area under the curve [230.0 vs. 520.8 vs. 501.9 (p = 0.16)]. CONCLUSIONS: The proposed individualized rehabilitation program supports a positive overall effect on anorectal dysfunction in MS patients.


Symmetry ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1813
Author(s):  
Lucia Figuli ◽  
Zuzana Zvaková ◽  
Vladimír Kavický ◽  
Tomáš Loveček

Most of the damage caused by an explosion is caused by a pressure effect. The magnitude of the pressure generated by the explosion is influenced by the external characteristics of the environment (surrounding objects, their arrangement, geometry, etc.) and internal characteristics (type of explosive, type of charge, booster and others). An effective combination of internal factors creates a symmetry that results in the highest possible value of pressure generated by the charge explosion. The paper focuses on the influence of the booster reaction on this symmetry. The scope of the paper is to understand the dependency of the blast wave pressure on the amount of used blaster to increase the efficacy of explosions on the environment and structures to increase the protection of affected structures. The open-air field tests were conducted using different types of explosives: trinitrotoluene and three different types of industrially made ANFO explosives (pure ammonium nitrate and fuel oil, ammonium nitrate and fuel oil plus aluminum powder, ammonium nitrate and fuel oil mixed with trinitrotoluene). The obtained data were compared with the analytical approach for setting the generated maximal pressure on the front of the blast wave.


2020 ◽  
Vol 4 (53) ◽  
pp. 35-42
Author(s):  
Sergey V. SHIL’KO ◽  
◽  
Dmitriy A. CHERNOUS ◽  
Andrey PLIGOVKA ◽  
◽  
...  

Strength and strain sensitivity of a thin polymer-ceramic coating in the form of a nanoporous anodic aluminum oxide impregnated with a piezoelectric polymer are studied. The coating is considered as a unidirectionally reinforced composite containing cylindrical polymer fibers oriented perpendicular to the coating surface. A three-phase micromechanical model of the specified material is proposed and the stress-strain state of the coating under the influence of uniformly distributed pressure is analyzed. As a result of solving the related problem of electroelasticity, calculated estimates of the specific piezoelectric sensitivity of the coating used as a pressure sensor and the maximum allowable pressure were obtained according to the strength criteria of the ceramic matrix and the plastic flow of the polymer filler. The article shows dependences of the indicated parameters on the volumetric content of the polymer for the coating, adhesively bonded to a non-deformable foundation and freely (without friction) lying on the foundation. At low volume content of polymer, the strength loss of coating is caused by local failure of matrix. At high filler content the transition of polymer into plastic state precedes to the beginning of matrix failure. After increasing the filler content above 80 % the value of maximal pressure according to yield criteria for polymer filler scarcely changes.


2020 ◽  
pp. 1-8
Author(s):  
Soo-Yong Kim ◽  
Il-Young Yu ◽  
Min-Hyeok Kang

BACKGROUND: During one-leg standing (OLS), optimum activity of the gluteus medius (Gmed), multifidus (MF), and quadratus lumborum (QL) muscles relies upon maintaining neutral lumbopelvic alignment. However, no studies have examined how using pressure biofeedback during OLS affects the activity of these muscles and the concomitant alignment of the pelvis and trunk. OBJECTIVES: The purpose of this study was to investigate the effect of pressure biofeedback on the activity of the Gmed, MF, and QL and the femoropelvic and trunk lean angles during OLS. METHODS: Twenty-four healthy males performed OLS with (PB+) and without (PB-) pressure biofeedback. For all OLS conditions, a pressure sensor was placed between the lateral surface of the humerus on the non-supporting side and the wall. Under the PB- condition, participants performed preferred OLS while the examiner measured the maximum pressure caused by trunk lean. Under the PB+ condition, participants were asked to perform at a threshold of 50% of the maximal pressure (PB+ 1 condition) and with minimal change in pressure (PB+ 2 condition). Muscle activities of MF, QL, and Gmed as well as the femoropelvic and trunk lean angles were measured under various OLS conditions. RESULTS: The activity of the Gmed, MF, and QL was greater under both PB+ conditions than under the PB- condition (p< 0.05). Also, both PB+ conditions resulted in a greater femoropelvic angle and reduced trunk lean angle. There were no significant differences in muscle activity, femoropelvic angle, or trunk lean angle between PB+ 1 and PB+ 2 (p> 0.05). CONCLUSIONS: These results suggest that pressure biofeedback is a useful modality for increasing the activity of the Gmed and trunk muscles, especially the MF muscle on the non-supporting leg side, and for preventing compensatory movements such as trunk deviation and pelvic lateral deviation during OLS.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Paulina Maślanka ◽  
Ryszard Korycki ◽  
Halina Szafrańska

AbstractThe aim of the article is to analyze the seams connecting the covering textiles in paraglider wing and estimate their physical strength. The most extreme flight parameters (the angle of attack and velocity) in the numerical model of the wing allow the determination of the mean pressure inside the contour and the maximal difference between the pressures on the inner and the outer material surfaces. The preprocessing stage and numerical calculations in Ansys environment consider three different covering materials. The tool Porous Media is used to create the objects of a given value of air permeability. The estimated parameter of seam is the maximal pressure difference between both sides of the covering material, which that interacts with the test results. The quality index of the seam is defined by the maximal force to seam rupture and relative elongation during rupture. The obtained results indicate that the seams are resistant to the pressure difference caused by the most extreme flight parameters.


Author(s):  
Kate Fetterplace ◽  
Lucy Corlette ◽  
Yasmine Ali Abdelhamid ◽  
Jeffrey J. Presneill ◽  
Michael T. Paris ◽  
...  

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3478 ◽  
Author(s):  
Tomasz Skrzek ◽  
Mirosław Rucki ◽  
Krzysztof Górski ◽  
Jonas Matijošius ◽  
Dalibor Barta ◽  
...  

This paper addresses the issue of metrological accuracy of instantaneous in-cylinder pressure measurement in a diesel engine test bed. In studies, the central unit has been the single-cylinder AVL 5402 engine. The pressure measurement was performed with a sensor designed for thermodynamic analysis, and the results were related to the crank angle, where two rotations corresponding to the four-stroke working cycle were denoted as angles between −360° and +360°. The novelty of this paper is the proposition of how to perform a type A uncertainty estimation of the in-cylinder pressure measurement and to assess its repeatability. It was demonstrated that repeatability of the measurement during the ignition process was difficult to estimate because of the phenomena that cannot ensure the repeatability conditions. To solve the problem, two methods were proposed. In one method, the pressure was measured in the subsequent cycles immediately after the ignition was turned off, and in another method, the engine was driven by a starter. The latter method provided maximal pressure values much lower than during usual tests. The obtained repeatability of measured pressure was %EV = 0.4%, which proved high capability of the evaluated measurement system.


SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A216-A216
Author(s):  
W Li ◽  
S Gakwaya ◽  
F Sériès

Abstract Introduction Soft palate muscles are crucial in the maintenance of UA patency. Different contraction tasks have been used to investigate tongue mechanical properties, but not to soft palate muscles. This study aimed to investigate the mechanical consequences of tongue and soft palate muscles fatigue in moderate-severe OSA patients. Methods 12 moderate and 8 severe patients with OSA were enrolled. Measurements include strength, endurance, and fatigue indices. During the soft palate fatiguing protocol, subjects were asked to develop repetitive intra-oral positive pressure during cheek-bulging maneuvers while wearing a mouth piece to keep the jaw opened. Tongue mechanical properties were also assessed using protrusion tasks with similar protocol. Subjects were encouraged to develop sustained maximal bulging pressure or tongue protrusion force for 5 sec every 10 sec until the peak pressure did not reach 85% of baseline maximal pressure for 2 consecutive times. The influence of age and BMI were also investigated. Results The sex, age were not significantly different between the 2 OSA groups. BMI was significantly higher in severe OSA patients (p&lt;0.05). Overall, the tongue maximal voluntary contraction force (MVC), endurance time and total muscle work were respectively positively associated with the ones obtained from the soft palate fatiguing task (rs=0.51, 0.43, 0.66, respectively). The MVC of both tongue and soft palate muscles were positively correlated with BMI in all subjects (rs=0.43, 0.5 respectively). The recovery time from soft palate fatigue was significantly longer in moderate than severe OSA patients (270s ± 192.3s and 120s ± 0, p =0.02). Interestingly, the recovery time was positively correlated with AHI in tongue fatiguing task, while negatively correlated with supine AHI and age in soft palate fatiguing task (p&lt;0.05). In both tasks, MVC was negatively correlated with the endurance time (p&lt;0.05). Conclusion Moderate patients are less likely to recover from soft palate muscle fatigue. A more severe apneic disease is associated with longer recovery time from tongue fatigue, but with shorter recovery time from soft palate fatigue. Our results suggest that alteration in tongue and velopharyngeal muscles function may differ according to the severity of disease. Support SBD from IUCPQ Foundation.


2019 ◽  
Vol 116 (11) ◽  
pp. 1887-1896 ◽  
Author(s):  
Adam B Veteto ◽  
Deborah Peana ◽  
Michelle D Lambert ◽  
Kerry S McDonald ◽  
Timothy L Domeier

Abstract Aims Cardiovascular disease remains the greatest cause of mortality in Americans over 65. The stretch-activated transient receptor potential vanilloid-4 (TRPV4) ion channel is expressed in cardiomyocytes of the aged heart. This investigation tests the hypothesis that TRPV4 alters Ca2+ handling and cardiac function in response to increased ventricular preload and cardiomyocyte stretch. Methods and results Left ventricular maximal pressure (PMax) was monitored in isolated working hearts of Aged (24–27 months) mice following preload elevation from 5 to 20mmHg, with and without TRPV4 antagonist HC067047 (HC, 1 µmol/L). In preload responsive hearts, PMax prior to and immediately following preload elevation (i.e. Frank–Starling response) was similar between Aged and Aged+HC. Within 1 min following preload elevation, Aged hearts demonstrated secondary PMax augmentation (Aged&gt;Aged+HC) suggesting a role for stretch-activated TRPV4 in cardiac hypercontractility. However, after 20 min at 20 mmHg Aged exhibited depressed PMax (Aged&lt;Aged+HC) suggestive of TRPV4-dependent contractile dysfunction with sustained stretch. To examine stretch-induced Ca2+ homeostasis at the single-cell level, isolated cardiomyocytes were stretched 10–15% of slack length while measuring intracellular Ca2+ with fura-2. Uniaxial longitudinal stretch increased intracellular Ca2+ levels and triggered Ca2+ overload and terminal cellular contracture in Aged, but not Aged+HC. Preload elevation in hearts of young/middle-age (3–12 months) mice produced an initial PMax increase (Frank–Starling response) without secondary PMax augmentation, and cardiomyocyte stretch did not affect intracellular Ca2+ levels. Hearts of transgenic mice with cardiac-specific TRPV4 expression exhibited PMax similar to 3- to 12-month control mice prior to and immediately following preload elevation but displayed secondary PMax augmentation. Cardiomyocytes of mice with transgenic TRPV4 expression were highly sensitive to mechanical stimulation and exhibited elevated Ca2+ levels, Ca2+ overload, and terminal contracture upon cellular attachment and stretch. Conclusion TRPV4 contributes to a stretch-induced increase in cardiomyocyte Ca2+ and cardiac hypercontractility, yet sustained stretch leads to cardiomyocyte Ca2+ overload and contractile dysfunction in the aged heart.


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