Neuroendocrine Cross-Talk and Axial Regulation of Embryonic Implantation

Early embryonic mortality has become a major issue of reproductive wastages and key constraint. The survivability of embryo during early embryonic life mostly depends on secretion of hormones. Development of embryo involves the coordinated function of different hormones synthesized in different endocrine glands. Exploring the complex intricate cellular and molecular mechanism interlaying between the neuroendocrine axial system environments shall facilitate to develop new strategies to augment survivability of embryo and success rate. Therefore, the chapter focused to explore the hidden cross talk and regulatory mechanisms to unfold the coordinating role of axial system in the embryonic implantation and also to explore the impact of climate change on embryonic implantation.

Reaction Forces and Rib Function During Locomotion in Snakes

Synopsis Locomotion in most tetrapods involves coordinated efforts between appendicular and axial musculoskeletal systems, where interactions between the limbs and the ground generate vertical (GV), horizontal (GH), and mediolateral (GML) ground-reaction forces that are transmitted to the axial system. Snakes have a complete absence of external limbs and represent a fundamental shift from this perspective. The axial musculoskeletal system of snakes is their primary structure to exert, transmit, and resist all motive and reaction forces for propulsion. Their lack of limbs makes them particularly dependent on the mechanical interactions between their bodies and the environment to generate the net GH they need for forward locomotion. As organisms that locomote on their bellies, the forces that enable the various modes of snake locomotion involve two important structures: the integument and the ribs. Snakes use the integument to contact the substrate and produce a friction-reservoir that exceeds their muscle-induced propulsive forces through modulation of scale stiffness and orientation, enabling propulsion through variable environments. XROMM work and previous studies suggest that the serially repeated ribs of snakes change their cross-sectional body shape, deform to environmental irregularities, provide synergistic stabilization for other muscles, and differentially exert and transmit forces to control propulsion. The costovertebral joints of snakes have a biarticular morphology, relative to the unicapitate costovertebral joints of other squamates, that appears derived and not homologous with the ancestral bicapitate ribs of Amniota. Evidence suggests that the biarticular joints of snakes may function to buttress locomotor forces, similar to other amniotes, and provide a passive mechanism for resisting reaction forces during snake locomotion. Future comparisons with other limbless lizard taxa are necessary to tease apart the mechanics and mechanisms that produced the locomotor versatility observed within Serpentes.

Patterns of Limb and Epaxial Muscle Activity During Walking in the Fire Salamander, Salamandra salamandra

Synopsis Salamanders and newts (urodeles) are often used as a model system to elucidate the evolution of tetrapod locomotion. Studies range from detailed descriptions of musculoskeletal anatomy and segment kinematics, to bone loading mechanics and inferring central pattern generators. A further area of interest has been in vivo muscle activity patterns, measured through electromyography (EMG). However, most prior EMG work has primarily focused on muscles of the forelimb or hindlimb in specific species or the axial system in others. Here we present data on forelimb, hindlimb, and epaxial muscle activity patterns in one species, Salamandra salamandra, during steady state walking. The data are calibrated to limb stride cycle events (stance phase, swing phase), allowing direct comparisons to homologous muscle activation patterns recorded for other walking tetrapods (e.g., lizards, alligators, turtles, mammals). Results demonstrate that Salamandra has similar walking kinematics and muscle activity patterns to other urodele species, but that interspecies variation does exist. In the forelimb, both the m. dorsalis scapulae and m. latissimus dorsi are active for 80% of the forelimb swing phase, while the m. anconaeus humeralis lateralis is active at the swing–stance phase transition and continues through 86% of the stance phase. In the hindlimb, both the m. puboischiofemoralis internus and m. extensor iliotibialis anterior are active for 30% of the hindlimb swing phase, while the m. caudofemoralis is active 65% through the swing phase and remains active for most of the stance phase. With respect to the axial system, both the anterior and posterior m. dorsalis trunci display two activation bursts, a pattern consistent with stabilization and rotation of the pectoral and pelvic girdles. In support of previous assertions, comparison of Salamandra muscle activity timings to other walking tetrapods revealed broad-scale similarities, potentially indicating conservation of some aspects of neuromuscular function across tetrapods. Our data provide the foundation for building and testing dynamic simulations of fire salamander locomotor biomechanics to better understand musculoskeletal function. They could also be applied to future musculoskeletal simulations of extinct species to explore the evolution of tetrapod locomotion across deep-time.

Complexity factors for static axial system in self-interacting Brans–Dicke gravity

This paper explores the physical attributes of a static axial source that induce complexity within the fluid in the background of self-interacting Brans–Dicke theory. Bel’s approach is used to split the Riemann tensor and construct structure scalars that involve physical features of the fluid in the presence of scalar field. Using the evolution equations derived from Bianchi identities as well as structure scalars, five complexity factors are identified which include constraints on the scalar field. Finally, the conditions of vanishing complexity are used to present solutions for an anisotropic inhomogeneous spheroid. It is concluded that scalar field is an additional source of complexity.

The Influence of Rotational Speed on the Wall Thickness and Mechanical Characteristic of Rotomouldable Plastics

This study is interested in the main parameter of this technique that uses a cubic container with an internal dimension of 100 mm and a cylindrical container 100 mm in diameter. We implemented the work in the fifth stage: In the first stage, we designed and manufactured the multi-axial system. In the second stage, the specimens were moulded from polyester, PVC, and polyethylene at a rotational speed axis of 5–120 rpm. The results from this stage indicated that the optimal rotational speed of the steady quality in dimensions and properties of the parts are 85, 100 and 115 rpm. The third stage was concerned with the effect of the speed of rotation on the thickness of the wall. The rotational speed of the axes was changed, and the thickness of the moulded walls was measured. The laboratory measurements revealed that the maximum compression ratio with the change of speed is at the speed of 115 rpm. The fourth stage was concerned with the effect of the speed of rotation on the value of tensile strength. The rotational speed of the axes was changed, and the tensile strength of the mould was measured. The tests revealed an improvement in the tensile strength at the speed of 115 rpm compared with the other speeds. The fifth stage utilised a cylindrical mould, which was re-worked in the previous stages, to investigate the effect of the speed of rotation on the thickness of the wall and mechanical specifications. Based on the conducted experimental tests, the influence of the rotational speed, which characterized the moulding process, on selected geometrical features of the mould was studied and analysed theoretically and numerically. The results showed an increase of about 5% in the compression ratio with increased rotation speed within the range of 85 to 115 rpm. There was also an improvement of about 7% in the tensile strength with increased rotational speed from 85 to 115 rpm. These results are due to the increase in the centrifugal force on the wall of the mould during the process. Also, the study was characterized by the production of the composite of polyethylene reinforced by iron screen wire, with improvement in the mechanical properties by about 300% compared to the base material.Â

Axially symmetric shear-free fluids in f(R,T) gravity

In this work, we have discussed the implications of shear-free condition on axially symmetric anisotropic gravitating objects in [Formula: see text] theory. Restricted axial symmetry ignoring rotation and reflection entries containing three independent metric functions is taken into account for establishment of instability range. Implementation of linear perturbation on constitutive modified dynamical equations yield evolution equation. This equation associates adiabatic index [Formula: see text] with material and dark source components of physical parameters defining stable and unstable regions in Newtonian (N) and post-Newtonian (pN) approximations. It is remarked that the axial system evolving under shear-free condition implicates high levels of stability in anisotropic environment.