X. G. Liu

Microwave-absorption properties of FeCo microspheres self-assembled by Al2O3-coated FeCo nanocapsules

FeCo microspheres, self-assembled by Al(2)O(3)-coated FeCo nanocapsules, were prepared by means of the arc-discharge technique to investigate application in electromagnetic-wave absorption. For the FeCo microspheres, a reflection loss (RL) exceeding -20 dB was obtained in the frequency range of 10.9-15.6 GHz for an absorber thickness of 1.2-2.0 mm. An optimal RL of -30.8 dB was found at 11.4 GHz for an absorber thickness of 2.0 mm. The excellent microwave-absorption properties are a consequence of a proper electromagnetic match in the microstructure of a strong natural resonance and of the shape anisotropy.

Dual nonlinear dielectric resonance and strong natural resonance in Ni/ZnO nanocapsules

The electromagnetic characteristics of Ni/ZnO nanocapsules were studied at 2–18 GHz. The dual nonlinear dielectric resonance and strong natural resonance at 16.6 GHz contribute to excellent electromagnetic absorption. A reflection loss (RL) exceeding −20 dB was calculated in 14–18 GHz for an absorber thickness of 2.05 mm, and RL exceeds −10 dB in the whole X-band (10–12.4 GHz) and the whole Ku-band (12.4–18 GHz) for a thickness of 2.50 mm. The equivalent circuit model was used to explain the dual nonlinear dielectric resonance, which is ascribed to a cooperative consequence of the core/shell interfaces and the dielectric ZnO shells.

Broadband electromagnetic-wave absorption by FeCo/C nanocapsules

Electromagnetic-wave absorption by FeCo/C nanocapsules has been investigated. In contrast to earlier reported materials, including other nanocapsules, the absorption amplitude of FeCo/C nanocapsules is found not to decrease with increasing absorption-layer thickness. A reflection loss (RL) exceeding −20 dB can be obtained for all frequencies within the 2–18 GHz range by choosing an appropriate layer thickness between 1.6 and 8.5 mm. The broadest bandwidth (RL values exceeding −10 dB) from 10 to 18 GHz, covering half of the X-band and the whole Ku-band, is obtained for a 2 mm layer.

Enhanced natural resonance and attenuation properties in superparamagnetic graphite-coated FeNi 3 nanocapsules

Electromagnetic (EM) characteristics of superparamagnetic graphite-coated FeNi(3) nanocapsules were studied at 2-18 GHz. Compared with FeNi(3) nanoparticles coated by an amorphous oxide layer, the natural resonance and attenuation properties of the graphite-coated FeNi(3) nanocapsules were dramatically enhanced, due to the coating of the graphite. Graphite layers can restrain the growth of FeNi(3) nanocapsules, increase the resistivity, enhance the resonance frequency, keep the real part of permeability almost constant at high frequency and increase the magnetic loss. As a result of enhanced natural resonance and attenuation properties, the FeNi(3)/C nanocapsules exhibit good EM absorption properties.

Protein kinase C controls lysosome biogenesis independently of mTORC1

Lysosomes respond to environmental cues by controlling their own biogenesis, but the underlying mechanisms are poorly understood. Here we describe a protein kinase C (PKC)-dependent and mTORC1-independent mechanism for regulating lysosome biogenesis, which provides insights into previously reported effects of PKC on lysosomes. By identifying lysosome-inducing compounds we show that PKC couples activation of the TFEB transcription factor with inactivation of the ZKSCAN3 transcriptional repressor through two parallel signalling cascades. Activated PKC inactivates GSK3β, leading to reduced phosphorylation, nuclear translocation and activation of TFEB, while PKC activates JNK and p38 MAPK, which phosphorylate ZKSCAN3, leading to its inactivation by translocation out of the nucleus. PKC activation may therefore mediate lysosomal adaptation to many extracellular cues. PKC activators facilitate clearance of aggregated proteins and lipid droplets in cell models and ameliorate amyloid β plaque formation in APP/PS1 mouse brains. Thus, PKC activators are viable treatment options for lysosome-related disorders.

Large reversible magnetocaloric effect in TbCoC2 in low magnetic field

A large reversible negative magnetic-entropy change Delta S(M) has been observed in TbCoC(2), accompanied by a second-order phase transition at 28 K. The maximum value of -Delta S(M) is 15.3 J kg(-1) K(-1) at 30 K for a magnetic-field change from 0 to 5 T, with the refrigerant capacity of 354 J kg(-1). In particular, also the large -Delta S(M)(max) of 7.8 J kg(-1) K(-1), is obtained for a small field change from 0 to 2 T. The large reversible Delta S(M) and the high reversible refrigerant capacity in low magnetic field indicate that TbCoC(2) may be a promising candidate for magnetic refrigeration at low temperatures

Intrinsic electrocaloric effects in ferroelectric poly(vinylidene fluoride-trifluoroethylene) copolymers: Roles of order of phase transition and stresses

The electrocaloric effects accompanied with the ferroelectric to paraelectric phase transitions in poly(vinylidene fluoride-trifluoroethylene) are investigated within the Landau–Devonshire theory. Just changing the nature of the phase transition from the first-order to the second-order reduces the isothermal entropy change, adiabatic temperature change and refrigerant capacity. The isothermal entropy change in the second-order transition is about one half of that in the first-order one, which is confirmed by experiments and is also consistent with the magnetocaloric counterpart. Converting to be film also leads to the reduction in electrocaloric effects, generally ascribed to the decrease of pyroelectric coefficients.

Comparative physiological and proteomic response to abrupt low temperature stress between two winter wheat cultivars differing in low temperature tolerance

Abrupt temperature reduction in winter wheat at either autumn seedling stage prior to vernalisation or early spring crown stage can cause severe crop damage and reduce production. Many studies have reported the physiological and molecular mechanisms underlying cold acclimation in winter wheat by comparing it with spring wheat. However, processes associated with abrupt temperature reduction in autumn seedling stage prior to vernalisation in winter wheat are less understood. In this study, physiological and molecular responses of winter wheat seedlings to abrupt low temperature (LT) stress were characterised in the relatively LT-tolerant winter wheat cultivar Shixin 828 by comparing it with the relatively LT-sensitive cultivar Shiluan 02-1 using a combination of physiological, proteomics and biochemical approaches. Shixin 828 was tolerant to abrupt LT stress, while Shiluan 02-1 exhibited high levels of reactive oxygen species (ROS) and leaf cell death. Significant increases in relative abundance of antioxidant-related proteins were found in Shixin 828 leaves, which correlate with observed higher antioxidant enzyme activity in Shixin 828 compared to Shiluan 02-1. Proteomics analysis also indicated that carbohydrate metabolism-related proteins were more abundant in Shiluan 02-1, correlating with observed accumulation of soluble sugars in Shiluan 02-1 leaves. Amino acid analysis revealed a strong response to LT stress in wheat leaves. A negative effect of exogenous sucrose on LT tolerance was also found. This study indicates that high ROS scavenging capacity and high abundance of photosynthesis-related proteins might play a role in winter wheat response to abrupt LT stress. In contrast, excess accumulation of soluble sugars might be disadvantageous for LT tolerance in the wheat cultivar Shiluan 02-1.

Magnetostructural coupling and magnetocaloric effect in Ni–Mn–In

Magnetic-field-induced martensitic phase transition and the concomitant change of volume are investigated in Ni–Mn–In alloy. A well-defined linear relationship is found between the quantity characterizing magnetic degree of freedom and the thermal expansion on behalf of structural degree of freedom, which demonstrates the magnetostructural coupling. Within the exchange-inversion model, such a linear relationship is theoretically derived and the magnetostructural correlation is elucidated. The lattice-entropy change contributes about one half of the total entropy change, suggesting that the magnetostructural coupling plays an important role in the magnetocaloric effect of Ni–Mn–In alloy.

Clathrin and AP2 Are Required for Phagocytic Receptor-Mediated Apoptotic Cell Clearance in Caenorhabditis elegans

Clathrin and the multi-subunit adaptor protein complex AP2 are central players in clathrin-mediated endocytosis by which the cell selectively internalizes surface materials. Here, we report the essential role of clathrin and AP2 in phagocytosis of apoptotic cells. In Caenorhabditis elegans, depletion of the clathrin heavy chain CHC-1 and individual components of AP2 led to a significant accumulation of germ cell corpses, which resulted from defects in both cell corpse engulfment and phagosome maturation required for corpse removal. CHC-1 and AP2 components associate with phagosomes in an inter-dependent manner. Importantly, we found that the phagocytic receptor CED-1 interacts with the α subunit of AP2, while the CED-6/Gulp adaptor forms a complex with both CHC-1 and the AP2 complex, which likely mediates the rearrangement of the actin cytoskeleton required for cell corpse engulfment triggered by the CED-1 signaling pathway. In addition, CHC-1 and AP2 promote the phagosomal association of LST-4/Snx9/18/33 and DYN-1/dynamin by forming a complex with them, thereby facilitating the maturation of phagosomes necessary for corpse degradation. These findings reveal a non-classical role of clathrin and AP2 and establish them as indispensable regulators in phagocytic receptor-mediated apoptotic cell clearance.