Eukaryotic initiation factor 6 regulates mechanical responses in endothelial cells

The repertoire of extratranslational functions of components of the protein synthesis apparatus is expanding to include control of key cell signaling networks. However, very little is known about noncanonical functions of members of the protein synthesis machinery in regulating cellular mechanics. We demonstrate that the eukaryotic initiation factor 6 (eIF6) modulates cellular mechanobiology. eIF6-depleted endothelial cells, under basal conditions, exhibit unchanged nascent protein synthesis, polysome profiles, and cytoskeleton protein expression, with minimal effects on ribosomal biogenesis. In contrast, using traction force and atomic force microscopy, we show that loss of eIF6 leads to reduced stiffness and force generation accompanied by cytoskeletal and focal adhesion defects. Mechanistically, we show that eIF6 is required for the correct spatial mechanoactivation of ERK1/2 via stabilization of an eIF6–RACK1–ERK1/2–FAK mechanocomplex, which is necessary for force-induced remodeling. These results reveal an extratranslational function for eIF6 and a novel paradigm for how mechanotransduction, the cellular cytoskeleton, and protein translation constituents are linked.

Dynamics of machines with ideal inertial motion

The term "inertioid" and its first design in 1936 was invented by engineer V. N. Tolchin. Despite the demonstration of unsupported motion using a physical model, the mystery of the inertioid has existed for almost a century. There are several theories explaining the motion of the inertioid (or mechanisms with inertial motion). These theories include the theory of friction, which proves that the movement of the device occurs due to the difference between the coefficients of friction and the coefficients of rolling resistance in contact between the bottom of the machine and the road. In some works, to explain the physical nature of this phenomenon, it is often legitimate to use A. Einstein's theory of relativity from a scientific point of view. In our opinion, the approach to the study of the process of motion of the inertioid should be based on the theory of the gravitational field. In the theory of relativity, A. Einstein notes that rapidly moving frames of reference create their own gravitational fields. Rotating weights create their own potential fields, since they are affected by centripetal accelerations. When the field of rotating loads is imposed on the gravitational field of the earth, accelerations appear that cause the movement of an inertioid (machines with an inertial mover). In fact, we constantly encounter this kind of overlap of potential fields in our daily life. For example, the effect of latitude on the value of the free fall acceleration of a body above the earth's surface is explained by the imposition of the earth's gravitational field of the potential field of its rotation around its axis. In the paper an inertioid with an idealized engine, which creates a constant driving (traction) force directed towards the movement has been investigated. As a result of the study, the equations of the translational motion of a machine with an ideal inertial engine were obtained, an expression for calculating its maximum speed was determined, and the maximum required engine power for the movement of a machine with an ideal inertial engine was determined.

THEORETICAL CONSIDERATIONS ON THE OPTIMIZATION OF THE WORKING PROCESS OF VARIABLE WIDTH PLOUGHS

The paper presents theoretical research conducted for the optimization of the working process of variable width ploughs. Thus, were determined multivariable regression functions for the traction force of the plough with variable working function of the control parameters: working depth, working width and working speed. The use of these theoretical considerations of the optimal points sought lead to the opportunity of making assessments on the possibilities to conduct their experimental validation. Conditions for an experimental plan were formulated to highlight such optimal points and the theoretical results were validated through experiments.

Indicators of the force interaction of the track and rolling stock when a freight car runs on long irregularities, taking into account the action of longitudinal forces

Authors describe formation mechanism of long irregularities of the railway track and the importance of their elimination for the track facilities. Based on the results of freight train operation modeling on long irregularities in the traction mode, an analysis of the processes occurring during the motion of heavy trains along a track with such deviations was carried out, modeling was carried out on the basis of the “Universal Mechanism” software package. Based on the results of the calculation, interaction between the track and the rolling stock in the vertical plane was assessed in terms of the magnitude of the vertical force and coeffcients: dynamics, stability margin, Nadal, unloading (in percent) of axle springs of freight car springs. Article analizes the nature of the infuence of the irregularity slope on the decrease in the vertical force transmitted from the wheel to the rail and the change in the traction force on the dynamics of freight cars in the train and passing on long irregularities of the longitudinal profle through the indicators of the vertical force.

Conceptual solutions for control systems of differential tensioners for belt conveyors

Differential tensioning devices for belt conveyors in general and intermediate drives of extended conveyors in the form of closed traction loops are a new type of automatic tensioning devices that differ from other known designs by the presence of a stepwise discrete belt tension control system with separation of compensation functions for belt stretching under load and control of its tension during the operation of the conveyor in order to create optimal modes of belt loading. The article analyzes the well-known and practical concepts of belt conveyor control systems in general. The possibility of controlling the traction force realized by the intermediate belt drive by controlling the tension of the traction and load-carrying belts is shown. On the basis of the analysis, conceptual solutions for control systems for differential tensioning devices of belt conveyors are proposed with the possibility of both autonomous use and application in the structure of an integrated conveyor control system. Possible structures of linear parts of differential tensioning devices are presented, as well as options for the implementation of executive parts that directly move tensioning elements.

Analytical Investigation of Roller Skew and Tilt in a Spherical Roller Bearing

The objective of this investigation was to analytically investigate the performance of a spherical roller bearing operating under various loading and speed combinations. In order to achieve the objective, a full six degree of freedom spherical roller bearing dynamic model was developed. The model was corroborated with results in open literature. An adaptive slicing method was developed to optimize the accuracy and computational effort of the roller force, skew, and tilt calculations. A comprehensive roller-race contact analysis in terms of slip velocity and contact area was then carried out to identify how bearing load and inner race speed variations change slip velocity and skew at the roller-race contact. The results from this investigation demonstrate that roller skew increases with inner race speed, while the roller tilt remains relatively constant. The inner race speed and roller slip velocity correlate well, which causes the traction force to increase and therefore produce greater skew. Skew and tilt angles also increase with applied axial load. However, at a certain load the skew angle begins to decrease.

Determination of the maximum traction force of the screw working body when piercing the soil

Laying of gas distribution pipelines, water mains, sewerage systems, power cables and communication cables is performed both by laying it in an open trench and by trenchless methods.

How Localized Z-Disc Damage Affects Force Generation and Gene Expression in Cardiomyocytes

The proper function of cardiomyocytes (CMs) is highly related to the Z-disc, which has a pivotal role in orchestrating the sarcomeric cytoskeletal function. To better understand Z-disc related cardiomyopathies, novel models of Z-disc damage have to be developed. Human pluripotent stem cell (hPSC)-derived CMs can serve as an in vitro model to better understand the sarcomeric cytoskeleton. A femtosecond laser system can be applied for localized and defined damage application within cells as single Z-discs can be removed. We have investigated the changes in force generation via traction force microscopy, and in gene expression after Z-disc manipulation in hPSC-derived CMs. We observed a significant weakening of force generation after removal of a Z-disc. However, no significant changes of the number of contractions after manipulation were detected. The stress related gene NF-kB was significantly upregulated. Additionally, α-actinin (ACTN2) and filamin-C (FLNc) were upregulated, pointing to remodeling of the Z-disc and the sarcomeric cytoskeleton. Ultimately, cardiac troponin I (TNNI3) and cardiac muscle troponin T (TNNT2) were significantly downregulated. Our results allow a better understanding of transcriptional coupling of Z-disc damage and the relation of damage to force generation and can therefore finally pave the way to novel therapies of sarcomeric disorders.