Contraction Movement Research Articles

Influences of floating ice on the vertical water entry process of a trans-media projectile at high speeds

It is of great significance to study the hydrodynamic process of trans-media projectiles passing through ice-water mixture at high speeds for the application of weapons in low-temperature environments of high-latitude water areas during the winter. Based on the volume of fluid (VOF) method and the Schnerr-Sauer cavitation model, the processes of a projectile vertically entering water (without floating ice) and passing through ice-water mixture without collision with ice at different initial high speeds were studied. The influences caused by the ice on the cavity evolution, flow field characteristics, hydrodynamic and ballistic characteristics were analyzed. The results showed that the floating ice alters the volume of air that is sucked into the cavity by hindering the diffusion and contraction movement of the liquid at the gas-liquid interface, changing the degree of cavitation and the formation and development modes of the cavity. It causes a different evolution of the cavity shape, delays the cavity closure, and affects the hydrodynamic force and ballistic characteristics of the projectile ultimately. With increasing velocity, the influence of ice on cavity shape reduces, however, on projectile ballistics, it enhances. The results can provide some theoretical references for further application research on trans-media weapons in floating ice environments.

Development and validation of a gene signature predicting the risk of postmenopausal osteoporosis.

AimsWe aimed to develop a gene signature that predicts the occurrence of postmenopausal osteoporosis (PMOP) by studying its genetic mechanism.MethodsFive datasets were obtained from the Gene Expression Omnibus database. Unsupervised consensus cluster analysis was used to determine new PMOP subtypes. To determine the central genes and the core modules related to PMOP, the weighted gene co-expression network analysis (WCGNA) was applied. Gene Ontology enrichment analysis was used to explore the biological processes underlying key genes. Logistic regression univariate analysis was used to screen for statistically significant variables. Two algorithms were used to select important PMOP-related genes. A logistic regression model was used to construct the PMOP-related gene profile. The receiver operating characteristic area under the curve, Harrell’s concordance index, a calibration chart, and decision curve analysis were used to characterize PMOP-related genes. Then, quantitative real-time polymerase chain reaction (qRT-PCR) was used to verify the expression of the PMOP-related genes in the gene signature.ResultsWe identified three PMOP-related subtypes and four core modules. The muscle system process, muscle contraction, and actin filament-based movement were more active in the hub genes. We obtained five feature genes related to PMOP. Our analysis verified that the gene signature had good predictive power and applicability. The outcomes of the GSE56815 cohort were found to be consistent with the results of the earlier studies. qRT-PCR results showed that RAB2A and FYCO1 were amplified in clinical samples.ConclusionThe PMOP-related gene signature we developed and verified can accurately predict the risk of PMOP in patients. These results can elucidate the molecular mechanism of RAB2A and FYCO1 underlying PMOP, and yield new and improved treatment strategies, ultimately helping PMOP monitoring.Cite this article: Bone Joint Res 2022;11(8):548–560.

Restricting Suffrage, Contracting Rights: Variations on Polanyi’s “Double Movement”

Karl Polanyi analyzed a “double movement” of society against the market in the nineteenth century. In our populist moment of the twenty-first century, we may be witnessing a movement in the other direction, of defenders of the market against the welfare state. A key method of implementing such a strategy is the motive of protecting “electoral integrity,” which may be in fact a rationale for restricting suffrage, especially among African American voters in central cities. The narrative of the stolen election of 2020, promoted by former President Donald J. Trump, may be providing the cover for targeting specific populations to disenfranchise them. Whereas expansion of suffrage in the nineteenth century was a method of supporting the working class, an opposite movement of contraction of suffrage may empower efforts to dismantle the welfare state and whatever is remaining of progressive taxation While the ravages of Neoliberalism might otherwise have been expected to propel a movement to defend society once again, the prospect at present may be to “double down” on defense of the market, to achieve a new form of authoritarian minority governance. According to Bruno Latour, a durable movement for the protection of society must build an alliance of labor with ecologists, to defend the earth, which forms the material foundation of Polanyi’s other fictional commodity, land.

Comparison of Heel Movement Between two Different Glue-on Type Shoes and Nailed Shoes in Thoroughbreds

Gluing an aluminum shoe onto equine hooves has been known to restrict heel movement and might cause interference with shock absorption and blood flow to the hoof. To investigate the effects of new glue-on type shoes on heel movement, 2 experiments that compared forelimb heel movement between conventional nailed shoes and flexible polyurethane glue-on shoes or Hanton-type shoes, which had 2 side clips for adhesive, were conducted on separate days. A displacement sensor was fixed on the heel to measure the forelimb's mediolateral heel movement. Exercise consisted of walking at 1.7 m/s, trotting at 4 m/s, cantering at 8 and 12 m/s for 30 seconds on a treadmill without a slope. The average heel expansion, contraction, and total heel movement (sum of the absolute expansion and contraction values) of 10 consecutive strides between the nailed shoes and glue-on shoes were compared using the paired t-tests. No significant differences in heel movement were observed between polyurethane glued shoes and nailed shoes regardless of gait. During trotting, Hanton shoes promoted significantly smaller heel expansion (14% decrease, P < 0.01) and larger heel contraction (11% increase, P = 0.03) compared to conventional nailed shoes, although no difference in total heel movement was observed. Furthermore, neither heel expansion nor contraction nor total movement in other gaits showed significant differences between Hanton shoes and conventional nailed shoes. The aforementioned results suggested that the new glue-on type shoes promoted similar heel movement compared to conventional nailed shoes.

Intraocular accommodative movements in monkeys; relationship to presbyopia

Our goal was to quantify the age-related changes in the dynamic accommodative movements of the vitreous and aqueous humor in iridic, aniridic, phakic and aphakic primate eyes.Six bilaterally iridic and four bilaterally iridectomized rhesus monkeys, ranging in age from 6 to 25 years, received a stimulating electrode in the midbrain Edinger-Westphal nucleus to induce accommodation, measured by a Hartinger coincidence refractometer. One of the four iridectomized monkeys underwent unilateral extracapsular and another monkey underwent intracapsular lens extraction. Eyes were imaged utilizing specialized techniques and contrast agents to resolve intraocular structures.During accommodation the anterior hyaloid membrane and the posterior lens capsule bowed backward. Central vitreous fluid and structures/strands moved posteriorly toward the optic nerve region as peripheral vitreous, attached to the vitreous zonule, was pulled forward by ciliary muscle contraction. Triamcinolone particles injected intravitreally were also observed in the anterior chamber and moved from the anterior chamber toward the cleft of the anterior hyaloid membrane and then further posteriorly into the vitreous-filled cleft between the vitreous zonule and the ciliary body pars plana. These accommodative movements occurred in all eyes, and declined with age.There are statistically significant accommodative movements of various intravitreal structures. The posterior/anterior fluid flow between the anterior chamber and the vitreous compartments during accommodation/disaccommodation represents fluid displacement to allow/facilitate lens thickening. The posterior accommodative movement of central vitreous fluid may result from centripetal compression of the anterior tips of the cistern-like structure attached to the vitreous zonule, and posterior displacement of the central trunk of the cistern during ciliary muscle contraction and centripetal muscle movement. The findings may have implications for presbyopia.

Identification of muscle activity in tongue motion during swallowing through medical image data

This paper presents a formulation to identify muscle activities from the variation in shapes of organs during swallowing. We assume that each organ consists of a three-dimensional hyperelastic body, and the contraction movement of the muscle is caused by a contractive inelastic stress in the organ. A function distributed in the organ domain to control the magnitude of the inelastic stress is chosen as a design variable in the same manner as the density in the topology optimization problem of density variation type. The identification problem is formulated as a problem of determining the design variable that minimizes an objective cost function defined by the squared L2 norm of the reaction force in the normal direction on the boundary when an enforced displacement to fit the varied boundary of the organ and the inelastic stress modeling the muscle activity are applied. The finite deformation problem of the hyperelastic body is analyzed using the finite element method. The direction of the muscle fiber is assumed to be the direction of the minimum principal stress obtained as the solution to the finite deformation problem. The solution to the identification problem is presented based on a scheme using the H1 gradient method for the topology optimization problem of density variation type. A numerical example using a previously developed model of the tongue is introduced to demonstrate the effectiveness of the proposed approach.

Physiological significance of pre- and post-ejection left ventricular tissue velocities and relations to mitral and aortic valve closures.

Tissue Doppler shows short duration velocity spikes during pre- and post-ejection (protodiastole). They have been assumed to be isovolumic contraction and relaxation movements, but this is not in accordance with newer studies. We examined 22healthy volunteers. Valve closures and openings were determined from spectral Doppler from LVOT and mitral inflow and transferred to colour tissue Doppler recordings for comparison with tissue velocities, colour M-mode and strain rate (SR). Pre-ejection positive velocity spikes were simultaneous in both walls, starting ca. 24.8±10.1ms after start QRS, duration 51.5±10.8ms, ending 10.2±11.5ms after mitral valve closure (MVC) (p<0.001). There were corresponding colour tracings and negative strain rate. Protodiastolic lengthening was predominant in the septum. Negative velocity spikes had a duration of 35.5±10.7ms, ending 9.5±14.7ms after aortic valve closure (AVC, p<0.001) in septum. During isovolumic relaxation, strain rate showed apical lengthening (Peak SR-0.72±0.50s-1 ) and basal shortening (Peak SR 0.44±0.63s-1 ). Electromechanical activation of the LV is simultaneous in septum and lateral wall, occurs before MVC, is terminated by MVC itself and is thus not isovolumic. Protodiastole is a short event of lengthening, predominantly in the septum. It may be the mechanism for valve closure and ends by AVC itself. Isovolumic relaxation occurs after this velocity spike, and is characterized by elongation of the apex, shortening of the base, thus showing a volume shift from base towards apex.

Fibroblast fusion to the muscle fiber regulates myotendinous junction formation

Vertebrate muscles and tendons are derived from distinct embryonic origins yet they must interact in order to facilitate muscle contraction and body movements. How robust muscle tendon junctions (MTJs) form to be able to withstand contraction forces is still not understood. Using techniques at a single cell resolution we reexamine the classical view of distinct identities for the tissues composing the musculoskeletal system. We identify fibroblasts that have switched on a myogenic program and demonstrate these dual identity cells fuse into the developing muscle fibers along the MTJs facilitating the introduction of fibroblast-specific transcripts into the elongating myofibers. We suggest this mechanism resulting in a hybrid muscle fiber, primarily along the fiber tips, enables a smooth transition from muscle fiber characteristics towards tendon features essential for forming robust MTJs. We propose that dual characteristics of junctional cells could be a common mechanism for generating stable interactions between tissues throughout the musculoskeletal system.

Effect of muscle fatigue on brain activity in healthy individuals

Fatigue is affected by both peripheral and central factors. However, the interrelationship between muscle fatigue and brain activity has not yet been clarified. This study aimed to clarify the effect of muscle fatigue due to sustained pinch movement on brain activity in healthy individuals using functional near-infrared spectroscopy (fNIRS). Ten healthy adults participated in the study. Pinch movement of isometric contraction was the task to be performed, and electromyogram of the first dorsal interosseous muscle and brain activity by fNIRS were measured in this period. The median power frequency (MdPF) was calculated as an index of muscle fatigue and the oxygen-Hb value in the bilateral premotor and motor areas was calculated as an index of brain activity. As a result, MdPF showed a significant decrease in the middle and later phases compared with that in the early phase (p < 0.05, p < 0.001, respectively) and a significant decrease in the later phase compared with that in the middle phase (p < 0.05). The oxygen-Hb values in the motor cortex were not significantly different between the analysis sections. The oxygen-Hb values in the premotor cortex was significantly increased in the later phase (p < 0.05) compared with that in the early phase. The premotor cortex was found to be specifically activated during muscle fatigue.

Design and research of multifunctional fast binding device

In order to solve the problem of hand injury and low efficiency of steel wire binding by hand, a multifunctional fast binding device is designed. It works on the principle of large pitch screw and is a sliding friction structure, which makes the binding work of steel bar change from manual reciprocating winding to linear expansion and contraction movement. At the same time, a counter is added to meet the needs of different steel wires. It is convenient to use and reduces the labor intensity of workers, High efficiency, in line with the construction site for equipment requirements.

Deformation model and experimental evaluation of a contractable and bendable wire-pulling mechanism with embedded soft tubes for a robotic tongue

Few physical models of oral and laryngeal systems for human speech movement exist for computer or mechanical simulators. In particular, a robot tongue mechanism that fully reproduces the deformation motion of the human tongue is lacking. The human tongue is an aggregate of muscles that is devoid of a skeleton. It possesses only a small hyoid. A mechanism that can drive and control the deformation of a soft body, such as the human tongue, along multiple degrees of freedom has not been realized to date. To solve this problem, a wire-pulling mechanism with embedded soft tubes is proposed. Using this mechanism, a flexible tongue that can be deformed along multiple degrees of freedom without breaking the wire is achieved. A prototype planar mechanism with two degrees of freedom that is capable of contraction and bending was fabricated. A deformation model that assumes a piecewise constant curvature (PCC) was formulated. Deformation tests confirmed that the prototype is capable of contraction and bending movements that are consistent with those of the model. Variations in the error with respect to the hardness of the deformable part are discussed, and the limits of the deformation model based on the PCC assumption are presented.

Retracted] Aerobics Exercise Posture Tracking and Recognition System Based on Wireless Smart Sensors

Wireless sensors are a new, high‐end, and popular exploration technology. The positioning and tracking of the human body are two important research issues in sensors. Aerobics is a widely popular sports item that is well‐loved by the general public and integrates gymnastics, dance, music, fitness, and entertainment. The application of smart sensors helps to improve the coordination and flexibility of movements. In order to deeply study whether wireless smart sensors can play a role in tracking and recognizing aerobics exercise postures, this article uses sensor design methods, motion analysis, and software and hardware equipment architecture methods to collect samples, analyze smart sensors, and streamline algorithms. And it creates a sensor model and system for posture tracking and recognition. When testing the best position for the placement of the sensor, first fix the sensor at a distance of 2.5 cm from the wrist section and at the middle of the lower arm, keep the upper arm still, and do the stretching and contraction movements of the lower arm. Repeat the exercise 5 times and measure the wrist. The movement curve of the juncture, the result shows that the measured juncture curve at a distance of 2.5 cm is basically the same as the actual winding curve, and the fixed position in the middle deviates more from the normal curve point, and its average error is within 0.9 cm, which is correct. To test the effectiveness of the algorithm again, a total of 8 volunteers’ data were collected during the experiment, and the duration was more than 25 seconds, and each normal posture tried to maintain stability and lasted for about 6 seconds. The statistical accuracy rate is 90.6%. It shows that the algorithm or the system designed in this paper has extremely high accuracy. It is basically realized that from the theory of wireless sensor network, a system model that can be used for posture tracking and recognition of aerobics is designed.

Dynamic Time Warping in Iris Biometric Recognition Process

In general, iris recognition systems with linear normalization model ignore the Pupil Light Reflex - PLR. The PLR is responsible for adjusting light intensity reaches the retina and causes nonlinear iris contraction and dilation movements that generates significant differences between enrolled images and test images. This paper has proposed a method to reduce the influence of iris dynamics examined by decidability (d) and Equal Error Rate (EER), obtained in the comparison between iris codes in different states of dilation. The method has used the Dynamic Time Warping (DTW) technique to compare the Histogram of Gradients Oriented (HoG) vectors extracted from the iris texture. In this way, the most discriminated characteristics between test images and the gallery had been aligned and compared, considering a nonlinear deformation of the iris tissue caused by the PLR. The experimental results, using dynamic images, indicate the system performance worsen when compared to images in different states of contraction. For a direct comparison between iris well contracted with well-dilated iris, the proposed method improves the decidability from 3.50 to 4.39 and the EER from 9.69% to 3.36%.

Compression spin bio-inspired arm: A conceptual model based on compression–torsion cubic mechanical metamaterials with variable cross-section

Robots are designed to achieve muscle contraction, body curling, stress response, and other complex movements. Inspired by the arm configuration and compression–torsion cubic mechanical metamaterials (CTCMM), the CTCMM with variable cross-section (V-CTCMM) and the offset CTCMM with variable cross-section (OV-CTCMM) by bionic designing are proposed. The novel microstructure can meet the shape requirement of the whole structure section. Through theoretical derivation for simplified cylinder models, the variation laws of torsion angle under torque in the V-CTCMM and OV-CTCMM are obtained. Three specific unit cells are studied under compression by numerical simulation and experiments. Compared with double rods CTCMM, the multi-rods CTCMM with variable cross-section (MRV-CTCMM) shows bigger torsion angle and larger stiffness. According to the characteristics of unit cells, the whole structure is constructed in the radial and axial direction with multiple expansion modes. Considering the stiffness of the structure in radial direction, straight rods and chiral rods construction methods are proposed to improve in-plane stiffness. The result shows the dumbbell structure can reach the best torsion angle among gradient structures in axial direction. With the progress of micro-nano manufacturing technology, 3D V-CTCMM shows a broad industrial application prospect in the fields of deformable structure, shape-memory controller, intelligent flexible microelectronics, and so on.

Mechanism for large-scale canyon deformations due to filling of large reservoir of hydropower project

Large storage dam projects may modify geo-environmental conditions in many ways. The reservoir impoundment of the 285.5 m high Xiluodu arch dam located on the Jinsha River (China) caused large-scale canyon deformations, including significant canyon contraction and uplift movements from reservoir to downstream valley. The dam experienced subsequent tilting towards upstream and raised a safety concern of the project. A Thermo-Hydro-Mechanical (THM) mechanism is proposed for this extraordinary behavior. Due to reservoir impounding and seepage, significant temperature drops and fluid pressure increase within the underlying geothermal limestone aquifer in a synclinal basin are primary root causes. Finite element THM simulations successfully reproduce these unique deformations. Recent observations of large quantities of thermalized discharge water downstream and high pore pressure in the limestone layer provide further support for the proposed mechanism. Furthermore, refined numerical modeling is adopted to evaluate the safety of Xiluodu dam subjected to potential larger canyon contractions. We conclude that these unprecedented phenomena are dominantly the consequence of THM response to regional hydrogeological evolution following the build-up of a large reservoir. The accumulated canyon contractions at the current stage would not pose a direct threat to the dam safety, but a tripled situation may cause severe safety issues.

Automatic Tracking of the Muscle Tendon Junction in Healthy and Impaired Subjects using Deep Learning.

Recording muscle tendon junction displacements during movement, allows separate investigation of the muscle and tendon behaviour, respectively. In order to provide a fully-automatic tracking method, we employ a novel deep learning approach to detect the position of the muscle tendon junction in ultrasound images. We utilize the attention mechanism to enable the network to focus on relevant regions and to obtain a better interpretation of the results. Our data set consists of a large cohort of 79 healthy subjects and 28 subjects with movement limitations performing passive full range of motion and maximum contraction movements. Our trained network shows robust detection of the muscle tendon junction on a diverse data set of varying quality with a mean absolute error of 2.55 ± 1 mm. We show that our approach can be applied for various subjects and can be operated in real-time. The complete software package is available for open-source use.

Three Dimensional Ultrasound of Pelvic Floor to Evaluate the Anatomical and Functional Changes of Primipara After Delivery

Objective: During pregnancy and childbirth, a series of remodeling processes may lead to the occurrence of pelvic floor dysfunction. Our aim was to explore the influence of different delivery methods on pelvic floor in primipara after delivery through three-dimensional (3D) ultrasound examination. Method: A total of 48 primiparas were selected as the study object. Among which, 21 primiparas underwent cesarean section were selected as observation group, 27 primiparas in vaginal delivery were selected as the control group. The 3D ultrasound examination of pelvic floor was carried out 6–8 weeks postnatally to observe and compare the prolapse of anterior, middle and posterior pelvic organs of parturient women in Valsalva movement. The posterior ureterovesical angel (PUA), urethral tilt angel (UTA), cervical mouth position (CMP), and bladder neck position (BNP) were measured. The changes of hiatus of levator ani muscle in patients with anal constriction, rest and Valsalva were observed and measured. Result: Compared with the data in control group, the number of cases of anterior, middle and posterior pelvic organ exfoliation in observation group was lesser, the UTA and BNP were higher, the CMP was lower, and the area of hiatus of levator ani muscle was smaller both at the time of calm, contraction and Valsalva movements. Conclusion: The damage of pelvic floor in primipara during transvaginal delivery is great. The 3D ultrasound is an objective and simple imaging method to screen the diseases of pelvic floor dysfunction.

Correlation between Physical Workload and Musculoskeletal Disorders Complaints among Nurses at Hospital

Introduction: Musculoskeletal disorders complaints occur due to excessive muscle contraction, excessive workloads and monotonous movements such as when nurses perform various nursing task such as moving patients, carrying patients from bed to wheelchair, awkward posture during infusion placement. This study aims to determine the correlation between physical workload and musculoskeletal disorders complaints among nurses at Regional General Hospital (RSUD) of Indramayu District in 2019. Methods: The design of this study uses quantitative with cross sectional. The method of data collection was crried by means of interview using the Nordic Body Map (NBM) questionnaire and observing the pulse calculation manually using a watch. Among the populations of 348 nurses, the samples of 75 nurses were selected based on the accidental sampling method. Statistical test used the chi-square test with a confidence level of 95% (α=0.05). Results: The study findings showed that most of 40 nurses who had heavy physical workload, 35 nurses (87.5%) had high musculoskeletal disorders complaints and 5 nurses (12.5%) had moderate musculoskeletal disorders complaints. On the other hand, of the 35 nurses who had moderate physical workload, 26 nurses (74.3%) experienced moderate musculoskeletal complaints and 9 nurses (25.7%) had high musculoskeletal disorders complaints. Chi-Square test results obtained p value = 0.000 (p &lt;0.05). Thus, it can be concluded that there was a significant correlation between physical workload and musculoskeletal disorders complaints among nurses. Conclusion: The heavier the physical workload, the higher the musculoskeletal disorders complaints among nurses.Keywords: musculoskeletal disorders, nurses, physical workload

Theoretical method to calculate pipeline thermal transient-induced walking rate considering nonlinear time-dependent soil resistance

Submarine pipeline was widely used to transport oil and gas in offshore petroleum exploitation. In practice, deep-water pipeline experiences several times of maintenance every year. This periodic open-up and shut-down operation causes cyclic rise and fall in the temperature of a pipeline, resulting in the periodic expansion and contraction of the pipeline. Due to the characteristics of heating-up operation, the expansion and contraction movement are symmetrical about different points, and it leads to the pipeline walking phenomenon. As a key factor, the axial soil resistance affects the walking displacement heavily. The shearing generated by expansion and contraction of a pipeline section causes intermitted consolidation of soil and cyclic increment in the equivalent soil resistance coefficient. This paper analysed pipeline walking of a free-end pipeline laid on even seabed with consideration of cyclic soil strength hardening. New driving mechanism for pipeline walking caused by thermal transient due to the influence of time-dependent soil resistance was proposed. A common theoretical method to calculate walking displacement was also established.

Normative values for gastric motility assessed with the 3D-transit electromagnetic tracking system.

The Motilis 3D-Transit system allows ambulatory description of transit patterns throughout the gastrointestinal tract and offers an alternative method for studying gastric motility. We aimed to establish normative values for gastric motility assessed with the method. A total of 132 healthy volunteers ingested the 3D-Transit capsule for assessment of gastrointestinal transit times. Recordings from 125 subjects were used for definition of normative values. Forty-six subjects were studied on two consecutive days. Recordings were reanalyzed using newly developed software providing information on gastric emptying (GE) as well as contraction frequency and movement during gastric contractions. The median GE time was 2.7hours (range 0.1-21.2). In 89% of subjects, the capsule passed the pylorus within a postingestion period of 6hours. The median frequency of gastric contractions was 3.1 per minute (range 2.6-3.8). The frequency was higher in women (3.2, range 2.7-3.8) than in men (3.0, range 2.6-3.5) and increased with age (0.004 per year) (P<.05). The median amplitudes were 35° (range 4-85) when based on rotation of the capsule and 11mm (range 6-31) when based on capsule change in position. The rotation amplitude was higher in women and decreased with increasing BMI (P<.05). The position amplitude was also higher in women and increased with the amount of calories in the test meal, but decreased with increasing BMI and age (P<.05). Day-to-day variation (P>.05) was considerable while inter-rater variability was small. We have established normative values for gastric motility assessed with the 3D-Transit system.