Enhanced plastic deformation ability of copper matrix composites through synergistic strengthening of nano-Al2O3 and Cr particles

The commercial application of Al2O3/Cu composites (ODS copper) with high Al2O3 content is consistently restricted by their plastic deformability. In order to synergistically improve the plastic deformability of Al2O3/Cu composites, Al2O3/Cu–Cr composites with different Cr contents are prepared by internal oxidation combined with heat treatment by replacing part of the Al2O3 particles with Cr phases heat treatment. The effects of Cr content on the microstructure and plastic deformability of Al2O3/Cu–Cr composites are investigated. It is found that the nano-Al2O3 (8 nm) and Cr (25 nm) particles are uniformly distributed in the copper matrix, and both reach a semi-congruent interface with copper matrix. Meanwhile, the copper matrix undergoes a transition from a [111]Cu hard orientation to a [100]Cu soft orientation, and the increase in Cr content leads to a more pronounced degree of recrystallization in the Al2O3/Cu–Cr composites. The results of geometric phase analysis (GPA) show that the coordinated deformability between Cr and Cu is better than that between Al2O3 and Cu. The elongation of 2.5Al2O3/Cu-0.3Cr composite increased to 24.48 % from 22.47 % of the Cr-free 2.8Al2O3/Cu composite. The results of tensile strength calculations show that the tensile strength of Al2O3/Cu–Cr composites is mainly dominated by matrix strengthening and Orowan strengthening induced by Al2O3 particles, while grain strengthening, dislocation strengthening, and Orowan strengthening induced by Cr particles play a secondary role. The correlation coefficient (R2) is 0.95 after fitting the experimental and theoretical values of tensile strength of Al2O3/Cu–Cr composites

PPARγ/mTOR Regulates the Synthesis and Release of Prostaglandins in Ovine Trophoblast Cells in Early Pregnancy

Trophoblast cells synthesize and secrete prostaglandins (PGs), which are essential for ruminants in early gestation to recognize pregnancy. Hormones in the intrauterine environment play an important role in regulating PGs synthesis during implantation, but the underlying mechanism remains unclear. In this study, co-treatment of sheep trophoblast cells (STCs) with progesterone (P4), estradiol (E2), and interferon-tau (IFN-τ) increased the ratio of prostaglandin E2 (PGE2) to prostaglandin F2α (PGF2α) and upregulated peroxisome proliferator-activated receptor γ (PPARγ) expression, while inhibiting the mechanistic target of rapamycin (mTOR) pathway and activating cellular autophagy. Under hormone treatment, inhibition of PPARγ activity decreased the ratio of PGE2/PGF2α and cellular activity, while activating expression of the mTOR downstream marker—the phosphorylation of p70S6K (p-p70S6K). We also found that the PPARγ/mTOR pathway played an important role in regulating trophoblast cell function. Inhibition of the mTOR pathway by rapamycin increased the ratio of PGE2/PGF2α and decreased the expression of apoptosis-related proteins after inhibiting PPARγ activity. In conclusion, our findings provide new insights into the molecular mechanism of prostaglandin regulation of trophoblast cells in sheep during early pregnancy, indicating that the PPARγ/mTOR pathway plays an important role in PGs secretion and cell viability

Anti-Eavesdropping by Exploiting the Space–Time Coupling in UANs

Due to the space–time coupling access, we find that anti-eavesdropping opportunities exist in underwater acoustic networks (UANs), where packets can be successfully received only by the intended receiver, but collide at the unintended receivers. These opportunities are highly spatially dependent, and this paper studies the case that linearly deployed sensor nodes directly report data toward a single collector. We found an eavesdropping ring centered around these linearly deployed sensor nodes, where the eavesdropper could steal all the reported data. Since the typical receiving-alignment-based scheduling MAC (TRAS-MAC) will expose the relative spatial information among the sensor nodes with the collector, the eavesdropper can locate the eavesdropping ring. Although moving the collector into the one-dimensional sensor node chain can degrade the eavesdropping ring to a point that constrains the eavesdropping risk, the collector’s location will be subsequently exposed to the eavesdropper. To efficiently protect the reported data and prevent the exposure of the collector’s location, we designed a slotted- and receiving-alignment-based scheduling MAC (SRAS-MAC). The NS-3 simulation results showed the effectiveness of the SRAS-MAC and the TRAS-MAC in protecting data from eavesdropping, which protect 90% of the data from eavesdropping in the one-eavesdropper case and up to 80% of data from eavesdropping in ten-eavesdropper cases. Moreover, unlike TRAS-MAC, which will expose the collector’s location, SRAS-MAC provides multiple positions for the collector to hide, and the eavesdropper cannot distinguish where it is

Effect of aging on properties and nanoscale precipitates of Cu-Ag-Cr alloy

In this paper, the Cu-0.52Ag-0.22Cr alloy was prepared by hot horizontal continuous casting. The effects of aging process on micro-hardness, electrical conductivity, and nanoscale precipitates of Cu-0.52Ag-0.22Cr alloy were studied. The electrical conductivity and micro-hardness increase significantly in the early aging time. With the extension of aging time, the electrical conductivity is basically unchanged and remains at a high level. While, the micro-hardness increases slowly, the change trend is different at 623 K, 723 K, and 773 K. The optimisation of process parameters occurs in 723 K for 2 h. At this time, the electric conductivity is 95.8% IACS and the hardness is 104.1 HV0.1. The XRD result shows that the Ag and Cr are precipitated in elemental form copper matrix. Further TEM shows that, Cr exists at the sub-boundary in the form of larger nanoscale precipitates (100-200 nm). While a large number of Ag nanoscale precipitates (8-10 nm) is dispersed on the copper matrix. The synergistic effect of Ag and Cr nanoscale precipitates significantly improved the properties of the alloy

Antitumor effects of anti-CD137/PD-1 mAbs againstne ID8 ovarian cancer.

<p>Mice (5/group) transplanted i.p. with 3 × 10⁶ ID8 cells 10 days previously were injected i.p. twice at 4 days interval with the indicated mAb combinations (0.5 mg of each mAb/mouse); survival was recorded (A, C) and mean survival time was calculated (B, D). The experiment was repeated once with similar results. E, Mice (8-9/group) transplanted i.p. with 3 × 10⁶ ID8 cells 3 days previously were injected i.p. twice at 4 days interval with 0.5 mg of control, anti-PD-1, anti-CD137 and anti-PD-1/CD137 mAb and their survival was recorded. *P < 0.05, **P < 0.01, compared with control mAb treated mice. </p