Rotation Mechanism Research Articles

Kinematic Characteristics of the Non-Throwing Arm During the Completion Phase of the Glide Shot Put in Elite Female Athletes: A Case Study

Background: This study analyzes the biomechanical contributions of the non-throwing arm during the completion phase of the glide shot put technique, focusing on its roles in performance optimization. Methods: Data from a Chinese elite female shot-putter were collected during a national championship, with three-dimensional kinematic analyses and Spearman correlation to assess joint displacement, velocity, and angular changes. Results: Distal joints of the non-throwing arm exhibited greater displacement but lower peak velocity than proximal joints. Angular changes showed a flexion trend in the elbow and shoulder, with brief extension phases in the elbow. During the completion phase, the shoulder velocity of the non-throwing arm positively correlated with shot put velocity (rs = 0.72, p < 0.05) but negatively correlated with the velocity of the elbow (rs = −0.46, p < 0.05), wrist (rs = −0.41, p < 0.05), and center of mass (rs = −0.66, p < 0.05). The elbow velocity positively correlated with shot put velocity (rs = 0.56, p < 0.05) but negatively correlated with velocities of the shoulder (rs = −0.59, p < 0.05), wrist (rs = −0.79, p < 0.05), and center of mass (rs = −0.91, p < 0.05). Wrist velocity exhibited similar correlations. Conclusions: These findings underscore the active role of the non-throwing arm in enhancing shot put performance by influencing the center of mass movement, rotational mechanics, and energy transfer, providing actionable guidance for elite training optimization.

Is rotational mechanics the link between strain and ejection fraction in patients with ventricular hypertrophy?

Abstract Introduction The reduction of global longitudinal strain (GLS) is an early marker of myocardial dysfunction. However, low GLS values do not provide information about the left ventricular ejection fraction (LVEF) because they can be decreased in patients with both reduced and preserved LVEF. Purpose To analyze the impact of rotational mechanics on the LVEF of patients with left ventricular hypertrophy and myocardial dysfunction. Methods We analyzed 248 patients with left ventricular hypertrophy, and divided them in two groups. Group 1 (n=104) with normal GLS (≥ 17%), and Group 2 (n=144) with decreased GLS (< 17%) due to myocardial dysfunction. We analyzed a) the rotational model ["twist" when the base and apex of the LV rotate in opposite directions, vs "rigid rotation" when the base and apex rotate in the same direction], and b) the rotational gradient (in degrees), as a result, in the case of twist, of the sum of basal and apical rotations (coded positive), and in the case of rigid rotation as a result of the difference between basal and apical rotations (coded negative). Results The 104 patients (Group 1) with normal GLS (≥ 17%), and therefore LVEF ≥ 50%, presented twist as the rotational model. Among the 144 pts (Group 2) with myocardial dysfunction (GLS < 17%), LVEF was < 50% in 34.7%. Twist was present in 83.3% of cases, and the remaining 16.7% exhibited rigid rotation. In this Group 2 of patients with myocardial dysfunction, the rotational gradient showed a good correlation with LVEF (r = 0.73; p < 0.001), such that in patients with twist, the values of the rotational gradient were progressively lower as LVEF decreased, until adopting negative values (pattern of rigid rotation) in those with more severe depression of LVEF as shown in Figure 2. Conclusion In patients with LVH and GLS impairment, the reduction of the rotational gradient translates into a deterioration of LVEF, providing additional information in the stratification of patients with myocardial dysfunction. Figure 1 Figure 2

Associations between systolic left ventricular rotational mechanics and peak left atrial reservoir strains - a three-dimensional speckle-tracking echocardiographic study

Abstract Introduction In systole, during left ventricular (LV) twist, the left atrium (LA) acts as a reservoir, its volume is the largest. In this phase of LA function, the direction of its wall movement is opposite to that of the LV wall, and can be quantitatively characterized using strains. Purpose The objective of the present study was to investigate the relationship between LV twist and LA strains as assessed simultaneously by three-dimensional speckle-tracking echocardiography (3DSTE) under healthy conditions by examining what happens when the above parameters are smaller or greater than the average. Methods In the present study, 157 healthy adults (mean age: 33.2 ± 12.7 years, 73 men) were involved. Complete two-dimensional Doppler echocardiography with 3DSTE-derived data acquisition were performed in all cases. 3DSTE-derived LA strains and LV rotational parameters were determined at a later date. Results Increased basal LV rotation was associated with a decreasing tendency of apical LV rotation and increased LV twist. Increased apical LV rotation was associated with a decreasing tendency of basal LV rotation and increased LV twist. Peak LA global circumferential (GCS) and area (GAS) strains proved to be reduced in case of the highest basal LV rotation, other peak LA strains did not show association with increasing basal LV rotation. Peak LA global radial strain (GRS) was highest in case of the lowest apical LV rotation. Peak LA global 3D strain (G3DS) was lowest in case of the highest apical LV rotation. All peak LA strains showed an increasing tendency of other strains but to different extent. With increasing peak LA-GRS, increasing peak LA global longitudinal strain (GLS), LA-GCS and LA-GAS could be detected, but only up to a point, beyond which further increase cannot be detected (except peak LA-G3DS). Increasing peak LA-GCS was associated with increase of all other strain values except for peak LA-G3DS. Increase of all peak LA strains could be seen with increasing peak LA-GLS, except for peak LA-GRS. From complex strains, with increasing peak LA-G3DS, increasing peak LA-GLS, LA-GCS and LA-GAS could be detected, but only up to a point, beyond which further increase cannot be detected (except peak LA-GRS). Increase of all peak LA strains could be detected with increasing peak LA-GAS, but only up to a point, beyond which further increase in peak LA strains cannot be detected. Only apical LV rotation proved to be significantly reduced in case of the highest peak LA-G3DS. Other peak global LA strains did not show any associations with basal and apical LV rotations. Conclusions In LV systole, LV rotational mechanics are associated with LA deformation represented by peak reservoir LA strains even in healthy circumstances.

Research on the Range of Stiffness Variation in a 2D Biomimetic Spinal Structure Based on Tensegrity Structures

Abstract: This paper presents a novel variable stiffness mechanism, namely the SBTDTS (Spinal Biomimetic Two-Dimensional Tensegrity Structure), which is constructed by integrating bioinspiration derived from biological spinal structures with the T-Bar mechanical design within tensegrity structures. A method for determining the torsional stiffness of the SBTDTS around a virtual rotational center is established based on parallel mechanism theory. The relationship between various structural parameters is analyzed through multiple sets of typical parameter combinations. Ultimately, the PSO (Particle Swarm Optimization) algorithm is employed to identify the optimal combination of structural parameters for maximizing the stiffness ratio, , of SBTDTS under different constraint conditions. This optimal configuration is then compared with the RAPRPM (a type of rotational parallel mechanism) under different values of , with an analysis of the distinct advantages of both variable stiffness structures.

Contribution of rotational mechanics to the differential echocardiographic diagnosis of myocardial hypertrophy versus myocardial infiltration

Abstract Introduction Increased left ventricular (LV) wall thickness can be caused by myocardial hypertrophy or infiltration. It is important to reach the correct diagnosis because of the major differences in prognosis and specific treatment. Purpose Our objetive was to analyze the contribution of LV rotational mechanics to the echocardiographic differential diagnosis between muscular hypertrophy versus myocardial infiltration. Methods We analyzed 107 patients with left ventricular hypertrophy [75 with myocardial hypertrophy secondary to hypertensive heart disease (HHD) and 32 patients with myocardial infiltration due to cardiac amyloidosis (CA)] using 2D-Echo speckle tracking. All patients had preserved LV ejection fraction (LVEF > 50%). We measured structural 2D-echocardiographic parameters, global longitudinal strain (GLS), and rotational parameters such as "Rotational Gradient" (°) between the LV basal rotation (°) and apical rotation (°) (twist if basal and apical rotations in opposite directions, or rigid rotation if basal and apical rotations in same directions) and "Wringing" as a normalized measure of Rotational Gradient per unit of longitudinal shortening (Rotational Gradient/GLS (°/%)), which includes the two movements that simultaneously occur during ventricular systole. SLG was obtained from 4-, 3- and 2-chamber apical planes, while basal and apical rotations were obtained from parasternal short-axis planes at these LV levels. Results Characteristics of study population are shown in Table 1. No differences in ventricular mass were observed between groups. The GLS was lower in the group of patients with CA, in addition to higher apical LS/basal LS+medial LS ratio. Twist Rotational Gradient showed no differences between the two groups, but its normalization according to ventricular shortening (Wringing) showed significant higher values in the group of patients with CA. Besides GLS <13.9% (AUC 0.92, p<0.0001, CI 95% 0.86-0.97), which is highly indicative of CA, wringing >1,39°/% (AUC 0.72, p <0.0001, CI 95% 0.61-0.82) proved to be a good supportive marker for CA diagnosis exhibiting a sensitivity of 75.0% and a specificity of 62.7%. Conclusion In patients with LV thickening and preserved LVEF, in addition to the information provided by myocardial longitudinal strain, the increase in ventricular wringing >1.39°/% is a useful parameter in the differential diagnosis of ventricular hypertrophy for CA.

Critical Filling Height of Embankment over Soft Soil: A Three-Dimensional Upper-Bound Limit Analysis

This paper investigates the critical filling height of embankments over soft soil using three-dimensional (3D) upper-bound limit analysis based on a rotational log-spiral failure mechanism. Soft soils are characterized by low shear strength and high compressibility, making the accurate determination of critical filling height essential for evaluating embankment stability. Unlike conventional two-dimensional (2D) analyses, the proposed 3D method captures the true failure mechanism of embankments, providing more realistic and reliable results. The upper-bound analysis equations are derived using the principle of virtual work and solved efficiently through the genetic algorithm (GA), which avoids the limitations of traditional loop and random searching algorithms. The proposed solution is validated by comparing it with existing studies on slope stability and demonstrates higher accuracy and computational efficiency. Parametric studies are conducted to evaluate the influence of the depth–height ratio (the ratio of soft soil depth to embankment height) on the failure width of the embankment, the critical failure surface, and the critical filling height. Results show that the critical failure surface is tangential to the bottom of the soft soil layer and the critical filling height increases as the depth–height ratio decreases. The findings provide a set of critical filling heights calculated under various soft soil depths, strength parameters, and embankment geometries, offering practical guidance for embankment design.

A Chemical Methods Use of Reduce the Effects of Heavy Water Toxicity on Human and the Environment

Our current specialized scientific study includes the process of using chemical methods to remove or treat pollutants in heavy water represented by sewage water that is produced from multiple sources such as that coming out of homes, and other water such as water resulting from industrial waste, or other water resulting from different sources. The chemical oxidation method was used through the establishment of oxidation ponds of different sizes with a depth of (50-150 cm), mechanical rotation, exposure to sunlight and oxygen in the atmosphere, followed by the activation of aerobic bacteria that decompose organic matter. The most important factors and basic ingredients that were adopted in the treatment methods are solar energy and water vapor condensation, agitation and movement of the mixture mechanically, exposure to air, decomposition of organic materials, chemical reactions that take place under fixed relative conditions.

Beam steering of Fabry Pérot antenna by using hybrid metasurfaces

This paper presents a new approach for designing a superstrate for the Fabry Pérot antenna, to achieve beam steering over the full azimuthal plane. The superstrate of the proposed antenna consists of a linearly graded metasurface (LgMS) and a constant phase partially reflecting surface (PRS). The hybrid metasurfaces offer gradual changes in the magnitude and phase of the reflection and transmission coefficient characteristics, which causes tilting of the main lobe direction.Further, the mechanical rotation of the superstrate structure in the azimuthal plane causes the main lobe direction to steer in the same plane. The proposed antenna operates from 4.33 GHz to 5.1 GHz with a maximum directivity of about 11 dBi and offers beam steering over complete azimuthal plane for frequencies below 4.8 GHz. The proposed structure can be used as a beam steering antenna for applications like air traffic control, satellite communication, shipboard communication, etc.

A Study on the Effect of Plastic Strain on Magnetic Phenomenology and Microstructure

The present work aspires to contribute to the discussion on the relationship between macroscopic measurements and microstructure, helping establish a methodology that will allow the quantitative assessment of the effect of strain on magnetic properties in the plastic deformation regime. In particular, we study the effect of strain on the magnetization process as a result of varying the anisotropy profile at the grain level. Results on micromagnetic calculations of hysteresis loops for various configurations of magnetic anisotropy are shown and discussed against the interplay between the energy terms involved in the calculations, namely anisotropy, demagnetizing, and exchange. The results are in line with previously obtained results using vector Preisach modeling with the Stoner–Wohlfarth model acting both as a switching and rotation mechanism. The hysteresis loop phenomenology is consistent with the emergence of a hard phase in the form of a boundary around soft grains which is assumed to be the result of the onset of compressive stresses in the plastic region. Future research will be oriented toward the study of the effect of the secondary peak in differential permeability, which is observed experimentally in the plastic deformation region, and its dependence on the angle of misalignment between the hard boundary and the soft grain.

Recent advances in centrifugal microfluidics for point-of-care testing.

Point-of-care testing (POCT) holds significant importance in the field of infectious disease prevention and control, as well as personalized precision medicine. The emerging microfluidics, capable of minimal reagent consumption, integration, and a high degree of automation, play a pivotal role in POCT. Centrifugal microfluidics, also termed lab-on-a-disc (LOAD), is a significant subfield of microfluidics that integrates crucial analytical steps onto a single chip, thereby optimizing the process and enabling high-throughput, automated analysis. By utilizing rotational mechanics to precisely control fluid dynamics without external pressure sources, centrifugal microfluidics facilitates swift operations ideal for urgent medical and field settings. This review provides a comprehensive overview of the latest advancements in centrifugal microfluidics for POCT, covering both theoretical principles and practical applications. We begin by introducing the fundamental operational principles, fluidic control mechanisms, and signal output detection methods. Subsequently, we delve into the typical applications of centrifugal microfluidic platforms in immunoassays, nucleic acid testing, antimicrobial susceptibility testing, and other tests. We also discuss the strengths and potential limitations of centrifugal microfluidic platforms, underscoring their transformative impact on traditional conventional procedures and their significant role in diagnostic practices.

Ageism as a form of occupational discrimination: A sociological conceptualization

The article is focused on the problem of occupational discrimination, with a specific focus on ageism as a prominent manifestation in contemporary workplaces, and its social effects. The article discusses two age categories of employees (the elderly and the youth) who most often experience ageism in the management practice of Russian companies. The conceptualization of ageism as a sociological problem includes a classification of its typical features. A key factor driving ageism is the pension age reform which causes mixed reactions in society. Employers’ discriminatory practices correlate with the legal and regulatory frameworks governing labor relations. The methodological section reviews the results of sociological research by the All-Russian Public Opinion Research Center (VCIOM) and independent sociological organizations that study ageism. The article argues that current recruitment practices, employee retention strategies, and rotation mechanisms in Russian organizations remain suboptimal and require further improvement. The negative social effects of ageism intensify tension in Russian society and the labor market, which together disrupts social balance in the context of economic instability and social challenges. Developing constructive solutions and modern strategies to combat ageism and broader occupational discrimination is essential for advancing interdisciplinary research in this field.

Growth kinetics of sintering neck and particle rotation mechanism of silver nanoparticles by molecular dynamics simulation and in-situ TEM observation

Growth kinetics of sintering neck and particle rotation mechanism of silver nanoparticles by molecular dynamics simulation and in-situ TEM observation

Structural insight into sodium ion pathway in the bacterial flagellar stator from marine Vibrio

Many bacteria swim in liquid or swarm on surface using the flagellum rotated by a motor driven by specific ion flow. The motor consists of the rotor and stator, and the stator converts the energy of ion flow to mechanical rotation. However, the ion pathway and the mechanism of stator rotation coupled with specific ion flow are still obscure. Here, we determined the structures of the sodium-driven stator of Vibrio, namely PomAB, in the presence and absence of sodium ions and the structure with its specific inhibitor, phenamil, by cryo-electron microscopy. The structures and following functional analysis revealed the sodium ion pathway, the mechanism of ion selectivity, and the inhibition mechanism by phenamil. We propose a model of sodium ion flow coupled with the stator rotation based on the structures. This work provides insights into the molecular mechanisms of ion specificity and conversion of the electrochemical potential into mechanical functions.

Situs Inversus: Organ inversion causes and its clinical implications

A finding that stands out in diagnostic imaging techniques and, certainly, in the operating room is the strange anomaly of Situs Inversus. Recent studies show the close relationship that exists between genetic traits and the probability of presenting this anomaly. Furthermore, the genetic traits found repeated in the population that presents it, seem to indicate a series of syndromes that imply a better understanding of this pathology. Today, Situs Inversus continues to be studied since it is still unknown the rotation mechanism, which not only may affect each patient's treatment, but also medicine in general.

Polarization Imaging Method for Detection of Lung Cancer Based on Symmetrical Single LCVR

ABSTRACTLung cancer ranks among the three most prevalent cancers worldwide. Polarization imaging technology can effectively distinguish between cancerous and normal tissues. The most commonly applied method for cancer detection is the dual‐rotating wave plate polarization imaging system (DWRPIS), which is cumbersome and prone to significant error due to 60 mechanical rotations. To address this, our experiment leveraged the stability of the Liquid Crystal Variable Retarder (LCVR) and, based on existing theoretical foundations for simplifying the use of LCVRs, designed a symmetric single‐LCVR polarization imaging system (SSLPIS) for the first time to detect lung cancer images. The SSLPIS is easy to operate, completing the entire acquisition process in just 150 s, with effective Mueller matrix imaging and an overall accuracy rate of over 90%, offering a faster and more precise detection method. This new approach provides an innovative pathway for the rapid detection of lung cancer.

Design and Validation of an Improved Rotational Variable Stiffness Mechanism

In various aspects of robotics, including human–robot interaction, the ability to dynamically adjust the apparent stiffness of an interaction (e.g., between the robot and its environment or between the robot and its payload) has become an important capability. Various means have been developed in recent years to achieve this, notable among them the so-called variable lever devices. In this paper, we present a new variable lever mechanism based on a gear–rack pair. This unique design combines the functionality of the lever itself with that of the stiffness-adjustment transmission. We show through simulations and hardware experiments the relatively large resulting range of achievable stiffness adjustment and efficient operation.

Field-Induced Polarization Rotation in Order-Disorder (K,Na)NbO3-Based Ferroelectrics.

Phase boundary is highly recognized for its capability in engineering various physical properties of ferroelectrics. Here, field-induced polarization rotation is reported in a high-performance (K, Na)NbO3-based ferroelectric system at the rhombohedral-tetragonal phase boundary. First, the lattice structure is examined from both macroscopic and local scales, implementing Rietveld refinement and pair distribution function analysis, respectively. The macroscopic phase coexistence at the phase boundary can be interchangeably rationalized with an average projection of collective local disordered units, exhibiting the order-disorder nature. The structural evidence of field-induced polarization rotation is provided by the in situ synchrotron study. Theoretical studies including density functional theory calculation and molecular dynamics simulation also predict the polarization rotation mechanism. The simulation result reveals the variation of the degree of ordering during the polarization rotation as a key feature of the boosted electrical properties in the order-disorder ferroelectric system. The discovery provides meaningful insight into the design of ferroelectrics with enhanced physical properties.

Swimming by Spinning: Spinning-Top Type Rotations Regularize Sperm Swimming Into Persistently Progressive Paths in 3D.

Sperm swimming is essential for reproduction, with movement strategies adapted to specific environments. Sperm navigate by modulating the symmetry of their flagellar beating, but how they swim forward with asymmetrical beats remains unclear. Current methods lack the ability to robustly detect the flagellar symmetry state in free-swimming spermatozoa, despite its importance in understanding sperm motility. This study uses numerical simulations to investigate the fluid mechanics of sperm swimming with asymmetrical flagellar beats. Results show that sperm rotation regularizes the swimming motion, allowing persistently progressive swimming even with asymmetrical flagellar beats. Crucially, 3D sperm head orientation, rather than the swimming path, provides critical insight into the flagellar symmetry state. Sperm rotations during swimming closely resemble spinning-top dynamics, with sperm head precession driven by the helical beating of the flagellum. These results may prove essential in future studies on the role of symmetry in microorganisms and artificial swimmers, as body orientation detection has been largely overlooked in favor of swimming path analysis. Altogether, this rotational mechanism provides a reliable solution for forward propulsion and navigation in nature, which would otherwise be challenging for flagella with brokensymmetry.

Molecular Insight into the Catalytic Mechanism of the Sesquiterpene Cyclase BcABA3.

BcABA3 is an unusual sesquiterpene synthase that lacks the conserved DDxxD and DTE/NSE motifs. Despite this, it can catalyze the conversion of farnesyl diphosphate to 2Z,4E-α-ionylideneethane. We used structure prediction, multiscale simulations, and site-directed mutagenesis experiments to investigate BcABA3 and its catalytic mechanism. BcABA3 has structural similarity to typical class I terpenoid cyclases in its active site. Based on simulation results, we identified two discontinuous glutamate residues, E124 and E88, which compensate for the absence of the aspartate-rich DDxxD motif. Quantum chemical calculations show that BcABA3 adopts a direct rotation mechanism for allyl cation isomerization rather than via the nerolidyl diphosphate. Then, it can achieve a successive proton transfer reaction, which is difficult to achieve by intramolecular rearrangement via the protruding outward carbonyl oxygen of A206. This reaction is then directed forward by two relatively stable intermediates containing a cation-conjugated double-bond structure. E124 is also proposed as the proton receptor in the final deprotonation to couple this step with 2Z,4E-α-ionylideneethane release. These findings provide valuable insight into the catalytic mechanisms of BcABA3 and can aid in its engineering, which will facilitate studies of abscisic acid biosynthesis.

Tunable elliptical cylinders for rotational mechanical studies of single DNA molecules.

The angular optical trap (AOT) is a powerful technique for measuring the DNA topology and rotational mechanics of fundamental biological processes. Realizing the full potential of the AOT requires rapid torsional control of these processes. However, existing AOT quartz cylinders are limited in their ability to meet the high rotation rate requirement while minimizing laser-induced photodamage. In this work, we present a trapping particle design to meet this challenge by creating small metamaterial elliptical cylinders with tunable trapping force and torque properties. The optical torque of these cylinders arises from their shape anisotropy, with their optical properties tuned via multilayered SiO2 and Si3N4 deposition. We demonstrate that these cylinders can be rotated at about three times the rate of quartz cylinders without slippage while enhancing the torque measurement resolution during DNA torsional elasticity studies. This approach opens opportunities for previously inaccessible rotational studies of DNA processing.