Nrf2 plays a critical role in the metabolic response during and after spaceflight

Space travel induces stresses that contribute to health problems, as well as inducing the expression of Nrf2 (NF-E2-related factor-2) target genes that mediate adaptive responses to oxidative and other stress responses. The volume of epididymal white adipose tissue (eWAT) in mice increases during spaceflight, a change that is attenuated by Nrf2 knockout. We conducted metabolome analyses of plasma from wild-type and Nrf2 knockout mice collected at pre-flight, in-flight and post-flight time points, as well as tissues collected post-flight to clarify the metabolic responses during and after spaceflight and the contribution of Nrf2 to these responses. Plasma glycerophospholipid and sphingolipid levels were elevated during spaceflight, whereas triacylglycerol levels were lower after spaceflight. In wild-type mouse eWAT, triacylglycerol levels were increased, but phosphatidylcholine levels were decreased, and these changes were attenuated in Nrf2 knockout mice. Transcriptome analyses revealed marked changes in the expression of lipid-related genes in the liver and eWAT after spaceflight and the effects of Nrf2 knockout on these changes. Based on these results, we concluded that space stress provokes significant responses in lipid metabolism during and after spaceflight; Nrf2 plays critical roles in these responses.

Compression of a Polar Orthotropic Wedge between Rotating Plates: Distinguished Features of the Solution

An infinite wedge of orthotropic material is confined between two rotating planar rough plates, which are inclined at an angle 2α. An instantaneous boundary value problem for the flow of the material is formulated and solved for the stress and the velocity fields, the solution being in closed form. The solution may exhibit the regimes of sliding or sticking at the plates. It is shown that the overall structure of the solution significantly depends on the friction stress at sliding. This stress is postulated by the friction law. Solutions, which exhibit sticking, may exist only if the postulated friction stress at sliding satisfies a certain condition. These solutions have a rigid rotating zone in the region adjacent to the plates, unless the angle α is equal to a certain critical value. Solutions which exhibit sliding may be singular. In particular, some space stress and velocity derivatives approach infinity in the vicinity of the friction surface.

Static Stress Changes and Triggering Imposed by Wenchuan Earthquake on Lushan M7 Earthquake

Some faults rupture the surface followed by coseismic dislocation, which causes space stress changes and transmits or imposes static stress on or to neighboring faults.The static stress triggering leads to the adjacent fault ruptured in advance, which means a Coulomb stress increase and triggers a new earthquake event. In recent two decades, some studies on stress triggering became important field of seismotectonics. The occurrence of both Wenchuan M8.0 earthquake and Japan M9.0 eathquake have arisen interest of many researchers, and obtained much new result and understanding.

Fatigue Tests of Overlapping Details for Orthotropic Steel Bridge Decks and Transverse Beams of Stay Cables

Rail-cum-road cable-stayed bridge with single cable plane is eccentric under moving load, overlapping details for orthotropic steel bridge decks and transverse beams of stay cables are in typical complex space stress condition. A fatigue test is performed to evaluate anti-fatigue performance of overlapping details under the combination of highway and light railway loads. A 1:1 model is adopted for the overlapping details, where a fatigue loading test for 2×106 cycles is carried out. Its test results show: the structural stress level is low, no crack is found on the test model after cyclic loading for 2×106 cycles, then load amplitude is gradually increased and no crack is found after cyclic loading for 4.25×106 cycles, finally a result is obtained that no fatigue crack will be found on the overlapping details for orthotropic steel bridge decks and transverse beams of stay cables within design life, because fatigue strength requirements are satisfied.

Existence of Optimal Energy Saving Parameters for Different Industrial Processes

It is demonstrated that energy input for fracture in many industrial processes can be optimised so that the energy cost of the process is minimised. Using a simple example of central crack it is shown that for a certain shape of the load pulse energy transmitted to the sample in order to initiate the crack has a strongly marked minimum. Received results indicate a possibility to optimise energy consumption of different industrial processes connected with fracture. Possible applications include drilling or rock pounding where energy input often accounts for the largest part of the process cost. Using this approach it will be possible to predict optimal operational parameters for bores, grinding machines, etc. and hence significantly reduce the process cost. In the second part of the paper the behaviour of energy input for initiation of fracture in conditions of contact interaction is studied. It is considered that a spherical particle is impacting the half-space. Stress field created as a result of the interaction can be estimated using the Hertz solution. Threshold particle velocity (and, hence, threshold kinetic energy) corresponding to initiation of rupture in the half-space can be found once the fracture criterion is defined. It will be shown that the value of this energy does significantly depend on load duration and has a marked minimum. Existence of energetically optimal modes of dynamic impact is claimed.