The mammalian Golgi apparatus is a highly dynamic organelle, which is normally localized in the juxtanuclear space and plays an essential role in the regulation of cellular homeostasis. While ...posttranslational modification of cargo is mediated by the resident enzymes (glycosyltransferases, glycosidases, and kinases), the ribbon structure of Golgi and its cisternal stacking mostly rely on the cooperation of coiled-coil matrix golgins. Among them, giantin, GM130, and GRASPs are unique, because they form a tripartite complex and serve as Golgi docking sites for cargo delivered from the endoplasmic reticulum (ER). Golgi undergoes significant disorganization in many pathologies associated with a block of the ER-to-Golgi or intra-Golgi transport, including cancer, different neurological diseases, alcoholic liver damage, ischemic stress, viral infections, etc. In addition, Golgi fragments during apoptosis and mitosis. Here, we summarize and analyze clinically relevant observations indicating that Golgi fragmentation is associated with the selective loss of Golgi residency for some enzymes and, conversely, with the relocation of some cytoplasmic proteins to the Golgi. The central concept is that ER and Golgi stresses impair giantin docking site but have no impact on the GM130-GRASP65 complex, thus inducing mislocalization of giantin-sensitive enzymes only. This cardinally changes the processing of proteins by eliminating the pathways controlled by the missing enzymes and by activating the processes now driven by the GM130-GRASP65-dependent proteins. This type of Golgi disorganization is different from the one induced by the cytoskeleton alteration, which despite Golgi de-centralization, neither impairs function of golgins nor alters trafficking.
Complete set of modes and the Hadamard function are constructed for a scalar field inside and outside a sphere in (D + 1)-dimensional de Sitter spacetime foliated by negative constant curvature ...spaces. We assume that the field obeys Robin boundary condition on the sphere. The contributions in the Hadamard function induced by the sphere are explicitly separated and the vacuum expectation values (VEVs) of the field squared and energy-momentum tensor are investigated for the hyperbolic vacuum. In the flat spacetime limit the latter is reduced to the conformal vacuum in the Milne universe and is different from the maximally symmetric Bunch-Davies vacuum state. The vacuum energy-momentum tensor has a nonzero off-diagonal component that describes the energy flux in the radial direction. The latter is a purely sphere-induced effect and is absent in the boundary-free geometry. Depending on the constant in Robin boundary condition and also on the radial coordinate, the energy flux can be directed either from the sphere or towards the sphere. At early stages of the cosmological expansion the effects of the spacetime curvature on the sphere-induced VEVs are weak and the leading terms in the corresponding expansions coincide with those for a sphere in the Milne universe. The influence of the gravitational field is essential at late stages of the expansion. Depending on the field mass and the curvature coupling parameter, the decay of the sphere-induced VEVs, as functions of the time coordinate, is monotonic or damping oscillatory. At large distances from the sphere the falloff of the sphere-induced VEVs, as functions of the geodesic distance, is exponential for both massless and massive fields.
We experimentally study the statistical properties of the energy fluxes between two trapped Brownian particles, interacting through dissipative hydrodynamic coupling, and submitted to an effective ...temperature difference ΔT, obtained by random forcing the position of one trap. We identify effective heat fluxes between the two particles and show that they satisfy an exchange fluctuation theorem in the stationary state. We also show that after the sudden application of a temperature gradient ΔT, the total hot-cold flux satisfies a transient exchange fluctuation theorem for any integration time, whereas the total cold-hot flux only does it asymptotically for long times.
The article presents the review of national and foreign publications reflecting aspects of development of medical blogosphere as communication space for medical workers and patients. The methodology ...of content analysis was applied. The main groups of medical bloggers (doctors, patients, nurses), characteristics of the blogs content, motivation for blogosphere posting are identified. The information and communication significance of the medical blogosphere is high and topical vectors are quite diversified. The development of the medical blogosphere testifies high level of demand for information forming the content of medical blogs both in patients and in colleagues-representatives of professional community.
•The influence of a very high neutron fluence, up to 3.2 × 1025 m−2, E>0.5 MeV, on the properties of VVER-440 weld was studied.•The effectiveness of recovery annealing at two different temperatures ...of the highly irradiated weld was investigated.•Long-term irradiation causes severe hardening and embrittlement and the formation of ultra-fine “black-dot “damage.•Recovery annealing at 475 °C results in significant recovery of mechanical properties, disappearance of the radiation-induced “black-dot” damage.
Mechanical testing and microstructural investigation on VVER-440 15Cr2MoV welds were carried out after irradiation and after recovery annealing treatment at two different temperatures (340 °C and 475 °C) for 100 h. The welds are part of the last surveillance chain of an Armenian nuclear power plant and have been irradiated for ~200,000 h at 270 °C, receiving extreme high fluence values (3.2 × 1025 m−2, E>0.5 MeV). Prolonged irradiation caused severe hardening and embrittlement. The increase of the yield strength and corresponding decrease in the uniform elongation are, 606 MPa and 10.2% respectively, when compared to the as-received state. Annealing at 340 °C did not show noteworthy recovery of the tensile properties. The recovery annealing treatment for 100 h at 475 °C resulted a significant recovery of the yield strength and relative uniform elongation (82% and 97% respectively) in conjunction with the disappearance of the irradiation-induced black-dot damage. The contribution of the observed irradiation-induced microstructural features to the total measured hardening was modelled using the Russel-Brown dispersion hardening model to qualitatively explain the observed hardening and recovery of the tensile properties after irradiation and annealing treatment respectively.
A modified fluctuation-dissipation theorem for a nonequilibrium steady state is experimentally checked by studying the position fluctuations of a colloidal particle whose motion is confined in a ...toroidal optical trap. The nonequilibrium steady state is generated by means of a rotating laser beam which exerts on the particle a sinusoidal conservative force plus a constant nonconservative one. The modified fluctuation-dissipation theorem is perfectly verified by the experimental data. It can be interpreted as an equilibriumlike fluctuation-dissipation relation in the Lagrangian frame of the mean local velocity of the particle.
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