Increased generation of reactive oxygen species (ROS) leads to oxidative stress in diabetes. Catalase is a highly conserved heme-containing protein that reduces hydrogen peroxide to water and oxygen ...and is an important factor decreasing cellular injury owing to oxidative stress. Hyperglycemic conditions increase oxidative stress and angiotensinogen gene expression. Angiotensinogen conversion to angiotensin II leads to a furtherance in oxidative stress through increased generation of reactive oxygen species. In this study, we utilized mice transgenically overexpressing rat catalase in a kidney-specific manner to determine the impact on ROS, angiotensinogen and apoptotic gene expression in proximal tubule cells of diabetic animals. Proximal tubules isolated from wild-type and transgenic animals without or with streptozotocin-induced diabetes were incubated in low glucose media in the absence or presence of angiotensin II or in a high-glucose media. Our results show that the overexpression of catalase prevents the stimulation of ROS and angiotensinogen mRNA in tubules owing to elevated glucose or angiotensin II in vitro. Additionally, overexpression of catalase attenuated ROS generation, angiotensinogen and proapoptotic gene expression and apoptosis in the kidneys of diabetic mice in vivo. Our studies point to an important role of ROS in the pathophysiology of diabetic nephropathy.
The Seebeck effect converts thermal gradients into electricity. As an approach to power technologies in the current Internet-of-Things era, on-chip energy harvesting is highly attractive, and to be ...effective, demands thin film materials with large Seebeck coefficients. In spintronics, the antiferromagnetic metal IrMn has been used as the pinning layer in magnetic tunnel junctions that form building blocks for magnetic random access memories and magnetic sensors. Spin pumping experiments revealed that IrMn Néel temperature is thickness-dependent and approaches room temperature when the layer is thin. Here, we report that the Seebeck coefficient is maximum at the Néel temperature of IrMn of 0.6 to 4.0 nm in thickness in IrMn-based half magnetic tunnel junctions. We obtain a record Seebeck coefficient 390 (±10) μV K
at room temperature. Our results demonstrate that IrMn-based magnetic devices could harvest the heat dissipation for magnetic sensors, thus contributing to the Power-of-Things paradigm.
The hinged-lid model was long accepted as the canonical model for fast inactivation in Nav channels. It predicts that the hydrophobic IFM motif acts intracellularly as the gating particle that binds ...and occludes the pore during fast inactivation. However, the observation in recent high-resolution structures that the bound IFM motif is located far from the pore, contradicts this preconception. Here, we provide a mechanistic reinterpretation of fast inactivation based on structural analysis and ionic/gating current measurements. We demonstrate that in Nav1.4 the final inactivation gate is comprised of two hydrophobic rings at the bottom of S6 helices. These rings function in series and close downstream of IFM binding. Reducing the volume of the sidechain in both rings leads to a partially conductive, leaky inactivated state and decreases the selectivity for Na
ion. Altogether, we present an alternative molecular framework to describe fast inactivation.
The effect of the cooling rate on the solidification process of liquid aluminium is studied using a large-scale molecular dynamics method. It is found that there are various types of short-range ...order (SRO) structures in the liquid, among which the icosahedral (ICO)-like structures are dominant. These SRO structures are in dynamic fluctuation and transform each other. The effect of the cooling rate on the microstructure is very weak at high temperatures and in supercooled liquids, and it appears only below the liquid-solid transition temperature. Fast cooling rates favour the formation of amorphous structures with ICO-like features, while slow cooling rates favour the formation of FCC crystalline structures. Furthermore, FCC and HCP structures can coexist in crystalline structures. It is also found that nanocrystalline aluminium can be achieved at appropriate cooling rates, and its formation mechanism is thoroughly investigated by tracing the evolution of nanoclusters. The arrangement of FCC and HCP atoms in the nanograins displays various twinned structures as observed using visualization analysis, which is different from the layering or phase separation structures observed in the solidification of Lennard-Jones fluids and some metal liquids.
The effect of the cooling rate on the solidification process of liquid aluminium is studied using a large-scale molecular dynamics method.
The cross sections of e+e-→π+π-hc at center-of-mass energies from 3.896 to 4.600 GeV are measured using data samples collected with the BESIII detector operating at the Beijing Electron Positron ...Collider. The cross sections are found to be of the same order of magnitude as those of e+e-→π+π- J/ψ and e+e-→π+π-ψ (2S), but the line shape is inconsistent with the Y states observed in the latter two modes. Two structures are observed in the e+e- → π+π- hc cross sections around 4.22 and 4.39 GeV / c 2 , which we call Y ( 4220 ) and Y ( 4390 ) , respectively. A fit with a coherent sum of two Breit-Wigner functions results in a mass of (4218.4 $+5.5\atop{-4.5 ± 0.9) MeV/c2 and a width of 66.0$+12.3\atop-8.3$±0.4 MeV for the Y (4220), and a mass of (4391.5 $+6.3\atop-16.8$ ± 1.0) MeV/c2 and a width of (139.5$+16.2\atop-20.6 ± 0.6) MeV for the Y (4390), where the first uncertainties are statistical and the second ones systematic. The statistical significance of Y ( 4220 ) and Y(4390) is 10σ over one structure assumption.
Here, in an analysis of a 2.92 fb–1 data sample taken at 3.773 GeV with the BESIII detector operated at the BEPCII collider, we measure the absolute decay branching fractions to be B(D0 → K–e+νe) = ...(3.505 ± 0.014 ± 0.033)% and B(D0 → π–e+νe) = (0.295 ± 0.004 ± 0.003)%. From a study of the differential decay rates we obtain the products of hadronic form factor and the magnitude of the CKM matrix element $f$ $^{K}_{+}$(0)|Vcs| = 0.7172 ± 0.0025 ± 0.0035 and $f$ $^{π}_{+}$(0)|Vcd| = 0.1435 ± 0.0018 ± 0.0009.
In this paper, the spin and parity of the Zc(3900)± state are determined to be JP = 1+ with a statistical significance larger than 7σ over other quantum numbers in a partial wave analysis of the ...process e+e- → π+π-J/Ψ. We use a data sample of 1.92 fb-1 accumulated at $ \sqrt{s}=4.23 $ and 4.26 GeV with the BESIII experiment. When parametrizing the Zc(3900)± with a Flatté-like formula, we determine its pole mass Mpole = (3881.2±4.2stat ±52.7syst) MeV/c2 and pole width Γpole = (51.8± 4.6stat ± 36.0syst) MeV. Finally, we also measure cross sections for the process e+e- → Zc(3900)+π- + c.c. → J/Ψπ+π- and determine an upper limit at the 90% confidence level for the process e+e- → Zc(4020)+π- + c.c. → J/Ψ π+π-.
Abstract
Ultrafast control of material physical properties represents a rapidly developing field in condensed matter physics. Yet, accessing the long-lived photoinduced electronic states is still in ...its early stages, especially with respect to an insulator to metal phase transition. Here, by combining transport measurement with ultrashort photoexcitation and coherent phonon spectroscopy, we report on photoinduced multistage phase transitions in Ta
2
NiSe
5
. Upon excitation by weak pulse intensity, the system is triggered to a short-lived state accompanied by a structural change. Further increasing the excitation intensity beyond a threshold, a photoinduced steady new state is achieved where the resistivity drops by more than four orders at temperature 50 K. This new state is thermally stable up to at least 350 K and exhibits a lattice structure different from any of the thermally accessible equilibrium states. Transmission electron microscopy reveals an in-chain Ta atom displacement in the photoinduced new structure phase. We also found that nano-sheet samples with the thickness less than the optical penetration depth are required for attaining a complete transition.
In this study, a yttria-stabilized zirconia (YSZ) ceramic matrix abradable sealing coating named 8YSZ-5 was successfully prepared by mixed solution precursor plasma spraying, and its thermal shock ...behavior was studied in detail. During the thermal shock cycles, the microstructure, residual stress and phase stability of the 8YSZ-5 coating were examined by using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) technique. The results show that the 8YSZ-5 coating has excellent thermal shock resistance through a 200-cycle thermal shock test at 1150 °C. During the thermal shock cycles, the spallation only existed in a small scale in the edge of the 8YSZ-5 coating, and the coating always maintains a stable phase composition of tetragonal structure. The residual stress study shows that the in-plane residual stress of the 8YSZ-5 coating is detected to be compressive stress, which increases with increasing the thermal shock cycles. The microstructure analysis shows that as the thermal shock test progresses, the number of the pores in the coating gradually decreases due to their spontaneous closure and the average size of the grains gradually increases. The mechanical properties investigation shows that the hardness and surface friction coefficient of the 8YSZ-5 abradable sealing coating increase gradually, while the bond strength of the coating decreases by 50% after 200 thermal shock cycles. The implications of this study are important for the design of advanced abradable sealing coatings prepared by the mixed solution precursor plasma spraying technology.
•YSZ coatings with hardness (HR15Y) lower than 60 were prepared by mixed solution precursor plasma spraying.•Nanostructures with high porosity contribute to the excellent thermal shock resistance of YSZ abradable coatings.•Phase stability during thermal shock cycles plays a role maintaining the coatings’ integrity•Compressive residual stress in coatings preventing propagation of micro-cracks during thermal shock cycles•Improvement on porosity, size of nanostructures and structure of cracks should be controlled in the future
Using a data set of 2.93 fb taken at a center-of-mass energy root s = 3.773 GeV with the BESIII detector at the BEPCII collider, we perform a search for an extra U(1) gauge boson, also denoted as a ...dark photon. We examine the initial state radiation reactions e(+)e(-) -> e(+)e(-) gamma(ISR) and e(+)e(-) -> mu(+)mu(-) gamma(ISR) for this search, where the dark photon would appear as an enhancement in the invariant mass distribution of the leptonic pairs. We observe no obvious enhancement in the mass range between 1.5 and 3.4 GeV/c(2) and set a 90% confidence level upper limit on the mixing strength of the dark photon and the Standard Model photon. We obtain a competitive limit in the tested mass range.
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