Terms Of Kinematic Parameters Research Articles

Melatonin Protects Bovine Spermatozoa by Reinforcing Their Antioxidant Defenses.

Cryopreserved semen is widely used in assisted reproductive techniques. Post-thawing spermatozoa endure oxidative stress due to the high levels of reactive oxygen and nitrogen species, which are produced during the freezing/thawing process, and the depletion of antioxidants. To counteract this depletion, supplementation of sperm preparation medium with antioxidants has been widely applied. Melatonin is a hormone with diverse biological roles and a potent antioxidant, with an ameliorative effect on spermatozoa. In the present study, we assessed the effect of melatonin on thawed bovine spermatozoa during their handling. Cryopreserved bovine spermatozoa were thawed and incubated for 60 min in the presence or absence of 100 μΜ melatonin. Also, the effect of melatonin was assessed on spermatozoa further challenged by the addition of 100 μΜ hydrogen peroxide. Spermatozoa were evaluated in terms of kinematic parameters (CASA), viability (trypan blue staining) and antioxidant capacity (glutathione and NBT assay, determination of iNOS levels by Western blot analysis). In the presence of melatonin, spermatozoa presented better kinematic parameters, as the percentage of motile and rapid spermatozoa was higher in the melatonin group. They also presented higher viability and antioxidant status, as determined by the increased cellular glutathione levels and the decreased iNOS protein levels.

A Simplified Mathematical Model of Pumped Hydrofoils

This paper presents a simplified mathematical model of a pumped hydrofoil (PH)—a surfboard elevated above water surface and connected to a tandem of hydrofoils by a strut. The PH is operated by a rider who stands on the surfboard and produces swinging up-and-down motions resulting in forward propulsion of the device. In the present paper, the description of the vertical motion of the PH is reduced to a linear oscillator excited by an oscillating mass coupled with the requirement that the weight is supported by dynamic lift of the foil(s). The inertial and damping influence of the hydrofoil(s) is accounted for by expanding unsteady lift force on the foil(s) in terms of kinematic parameters. The restoring term of the oscillator is associated with the phenomenon of automatic stabilization of shallowly submerged hydrofoils. The latter effect manifests itself in that when a hydrofoil approaches free surface, its lift decreases, and when it moves away from free surface, its lift increases. The analytical solution of the pumping foil mass-spring type forced oscillations equation allows one to calculate the flapping motion of the foil(s) and, thereafter, the period-averaged thrust generated by the PH. The resulting speed has been estimated on an assumption that the device enters its cruising mode when the thrust becomes equal to the drag, the latter comprising viscous, wave, and induced drag components. The model under discussion allows one to relate the main parameters of the system to its performance and, hopefully, provides further insight into the pumped hydrofoil phenomenon, its design methodology, and operation strategy. The review part of the paper focuses on two aspects of the problem: hydrodynamic behavior of the hydrofoil(s) in proximity to free water surface and their propulsion due to oscillations.

Characteristics of Aerobic Resistance Strength Training With Different Load Intensity Based on Acceleration Sensor

Objective: To compare the changes of kinematics and dynamics indexes of deep squat, bench press and hard pull in order to provide basis for the application of these three kinds of resistance strength training methods. Methods: The kinematic and dynamic characteristics of 30 young men in deep squat, bench press and hard pull were measured by the real-time wireless sensor motion capture and mechanical evaluation system of the wearable FAB. Results: In terms of kinematic parameters under 40%1RM and 80%1RM load, there were significant differences(P < 0.05) in flexion angle of deep squat hip joint, knee joint, hard pull hip joint and knee joint. There were significant differences in the angular velocity of trunk forward flexion and trunk extension, shoulder extension angle velocity of horizontal push, and flexion angular velocity of hard pull knee joint (P < 0.05), and significant differences were found in hip joint flexion angle acceleration, elbow extension angular acceleration in horizontal push, elbow flexion and knee joint flexion angle acceleration (P < 0.05). Conclusion: Hip joint and knee joint are the most important in deep squat and hard pull angle, angular velocity and angular acceleration, elbow joint is the most important one in bench press angle, angular velocity and angular acceleration.

Cluster analysis reveals seasonal variation of sperm subpopulations in extended boar semen.

This study aimed to identify motile sperm subpopulations in extended boar semen and to observe the presumptive seasonal variation in their distribution. Data from 4837 boar ejaculates collected over a two-year period were analyzed in terms of kinematic parameters by Computer Assisted Sperm Analysis (CASA). Individual sperm data were used to determine subgroups of motile sperm within the ejaculates using cluster analysis. Four motile sperm subpopulations (SP) were identified, with distinct movement patterns: SP1 sperm with high velocity and high linearity; SP2 sperm with high velocity but low linearity; SP3 sperm with low velocity but high linearity; and SP4 sperm with low velocity and low linearity. SP1 constituted the least overall proportion within the ejaculates (P < 0.05). Season of semen collection significantly influenced the different proportions of sperm subpopulations. Spring was characterized by similar proportions of SP1 and SP4 (NS) and higher proportions of SP3. Summer brought a decrease in both subgroups containing fast sperm (SP1 and SP2) (P < 0.05). During autumn, increases in SP2 and SP4 were recorded. Winter substantially affected the proportions of all sperm subpopulations (P < 0.05) and SP2 became the most represented subgroup, while SP1 (fast and linear) reached its highest proportion compared to other seasons. In conclusion, extended boar semen is structured in distinct motile sperm subpopulations whose proportions vary according to the season of collection. Summer and autumn seem to have a negative impact on the fast and linear subpopulation. Cluster analysis can be useful in revealing differences in semen quality that are not normally detected by classical evaluation based on mean values.

Kinematic parameters of pure‐ and converted‐mode waves in elastic orthorhombic media

ABSTRACTI derive the kinematic properties of single‐mode P, S1, and S2 waves as well as converted PS1, PS2, and S1S2 waves in elastic orthorhombic media including vertical velocity, two normal moveout velocities defined in vertical symmetry planes, and three anelliptic parameters (two of them are defined in vertical symmetry plane and one parameter is the cross‐term one). I show that the azimuthal dependence of normal moveout velocity and anellipticity is different in phase and group domains. The effects on‐vertical‐axis singularity and on‐vertical‐axis triplication are considered for pure‐mode S1 and S2 waves and converted‐mode S1S2 waves. The conditions and properties of on‐vertical‐axis triplication are defined in terms of kinematic parameters. The results are illustrated in four homogeneous orthorhombic models and one multilayered orthorhombic model with no variation in azimuthal orientation for all the layers.

Innovative Tools for Real-Time Simulation of Dynamic Systems

In this paper, we present a software architecture, based on RTAI-Linux, for the realtime simulation of dynamic systems and for the rapid prototyping of digital controllers. Our aim is to simplify the testing phase of digital controllers by providing the real-time simulation of the plant with the same interface used for the communication between the control applications and real plant. This unified interface, based on the COMEDI library, allows to switch the controller from the simulated to the real plant without any modification of the control software. Moreover, a set of tools for helping the users in the development of the real-time simulation tasks of the plants have been developed. A great attention has been posed in the automatic generation of symbolic kinematic and dynamic models of robotic manipulators from a description of the robot in terms of kinematic parameters and inertia/center of mass of each link. The system, besides being useful for rapid prototyping of mechatronic control systems, may be used for fault detection, and also as a teaching tool in Mechatronic/Digital Control Courses. A case study, the real-time simulation and control of the PUMA 560 manipulator, is presented and discussed.

Use of incompatible displacement modes in a finite element model to analyze the dynamic behavior of unreinforced masonry panels

A finite element model, where a non-conforming quadrilateral element is utilized, capable of analyzing the dynamic nonlinear behavior in a biaxial stress field of unreinforced masonry panels is presented. For the material, the linear elastic-plastic constitutive law is adopted. The formulation for the linear element and the extension for the linear elastic-plastic element are proposed. The solution is carried out by a direct step by step integration procedure in time domain, based on the Newmark method of the equilibrium equations, inclusive of inertial and damping actions, the latter evaluated using the Rayleigh hypothesis. The procedure was implemented in a computer program and verified by the analysis of an unreinforced masonry shear panel, the dynamic behavior of which was analyzed experimentally [1, 2]. The comparisons between the numeric results and laboratory test measurements show good agreement, proving the good performance of the non-conforming quadrilateral element also for time-dependent and markedly nonlinear analyses. In addition, the case of Parma Cathedral Bell-Tower subjected to a dynamic excitation available in literature, was analyzed using the proposed model. The same case was approached by a reliable finite element code [3], using quadratic serendipity elements and a more dense mesh than in the previous analysis. The results, in terms of kinematic parameters, stress and strain fields, etc. obtained by the two models, agree, proving that the use of a non-conforming quadrilateral element leads to analyses which are computationally economical and simple to use in input.