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Crystallographically anisotropic SmCo5 nanoflakes were fabricated directly by one-step surfactant-assisted high energy ball milling (HEBM) of Sm17Co83 ingot powders for 5 h in heptane and oleic acid (OA) without preprocessing or further annealing. The SmCo5 nanoflakes have a strong [001] out-of-plane texture. The thickness of nanoflakes is in the range of 8-80 nm while their length is 0.5-8 μm. The surfactant OA plays an important role in the formation of SmCo5 nanoflakes. HEBM of SmCo5 ingots in heptane without OA resulted in the formation of magnetically isotropic more or less equiaxed SmCo5 particles with a size of 2-30 (m. Closely packed "kebablike" SmCo5 nanoflakes were formed by HEBM in heptane with 15 wt % OA. HEBM in 150 wt % OA led to well-separated nanoflakes instead of the closely packed kebablike nanostructure. This resulted in the enhanced [001] out-of-plane texture. In-plane transmission electron microscope examination showed that the SmCo5 nanoflakes were composed of grains with sizes in the range of 4-8 nm. Coercivities of about 18.0 kOe were obtained for the anisotropic SmCo5 nanoflakes. [ABSTRACT FROM AUTHOR]

Composite magnets containing Sm-Co and Co phases were prepared from high-energy-milled Sm-Co and Sm-(Co,Fe,Mn) powders with the 1:5 and 2:7 stoichiometries blended with a micron-size Co powder. The blending was done via high-energy milling in argon or heptane; the blends were subsequently consolidated at 650 °C and subjected to a 65% plastic deformation at 800 °C. Both the premilling of Sm-Co component and the processing environment markedly influenced the microstructure and magnetic properties of the resulting composites. After blending in heptane, the composites made from the 1:5 and Co phases still contained these two phases in addition to the emerging 2:17 phase. Addition of oleic acid as a surfactant led not only to a more uniform and refined microstructure but also to a significant oxidation. After blending in argon, the composites made from the 1:5(2:7) and Co phases exhibited a two-phase structure with 80 nm Co inclusions embedded in a 2:17 matrix. Unfortunately, the newly formed 2:17 phase did not inherit the texture induced in the 1:5(2:7) precursors by the hot-deformation. Although the argon-blended composites were magnetically superior to the heptane-blended ones, they exceeded the maximum energy product of the single-alloy magnets with the same overall composition only when the Sm(Co,Fe,Mn)5 powder had been used as a precursor. The highest properties obtained were 8.8 kG, 6.3 kOe, and 13.1 MGOe for the remanence, coercivity, and energy product, respectively. [ABSTRACT FROM AUTHOR]

Electric propulsion systems for space exploration require materials and components that can perform reliably under a vacuum of 10-5 Torr and at temperatures of over 400 °C. Scanning electron microscopy analysis shows that when Sm–Co magnets are exposed to temperatures up to 550 °C for up to 240 h in a vacuum of 10-5 Torr, the surface alteration is morphologically similar to oxidation in air. However, the scale of the affected region is much smaller and consists of about 1–2 μm of a top outermost Sm-depleted oxide layer and about 10–20 μm of a more complex layer in which the constituent atoms redistribute with oxygen penetration. No excessive Sm depletion was observed in the second layer. For all Sm–Co magnet samples, the maximum energy product decreased by less than 10% even at temperatures of 100 °C above their specified maximum operating temperature TM. The residual induction of the magnets with TM=550 °C decreased by 8.5% after baking at 700 °C under vacuum for 240 h. [ABSTRACT FROM AUTHOR]

This work reports the effect of NdF3, DyF3, and CaF2 additions on the electrical resistivity and magnetic properties of Pr–Fe–B hot-pressed and die-upset permanent magnets. Composite magnets were synthesized from ground Pr14.5Fe79.5B6 melt-spun ribbons blended with 5 wt % of fluoride fine powders and consolidated by hot pressing at 650 °C, followed by die upsetting at 800 °C. While CaF2 is stable at the processing temperatures, the rare earth atoms separate from their fluorides to a certain degree with the assistance of the Pr-rich phase from the magnet matrix. Addition of fluorides increased the resistivity of the hot-pressed specimens by more than 200%. The resistivity of the die-upset specimens measured perpendicularly to the direction of the applied pressure, which is also the direction of magnetization, is, however, only slightly increased compared to the magnet counterparts without the fluoride addition. The intrinsic coercivity of Pr14.5Fe79.5B6 die-upset specimens is increased from 14.5 kOe to 15.3, 17.1, and 17.7 kOe for the addition of CaF2, DyF3, and NdF3, respectively, at a slight expense of the residual flux. [ABSTRACT FROM AUTHOR]

Utilizing the chemical reduction of FeCl2 with NaBH4 in the presence of 2:17 Sm–Co powders, we synthesized composite Sm(Co0.699Fe0.213Cu0.064Zr0.024)7.4/nano-Fe anisotropic hard magnetic powders. The average particle size of the hard magnetic core powder was 21 μm while the soft magnetic Fe nanoparticles deposited uniformly on the core powder had a particle size smaller than 100 nm. Different reaction protocols, such as immersion of the hard magnetic core powder in each reagent, the use of microemulsion (micelle) technique, or doubling the weight ratio of FeCl2 to core powder, led to different degrees of magnetic coupling of the hard and soft magnetic components of the composite powder. A reaction time of 180 s led to deposition of 3.5 wt % Fe nanoparticles and improved magnetic properties of the composite powder compared to the uncoated Sm(Co0.699Fe0.213Cu0.064Zr0.024)7.4 powder. The respective magnetic hysteresis parameters were 4πM18 kOe=11.3 kG, 4πMr=11 kG, and iHc>20 kOe with a smooth demagnetization curve. [ABSTRACT FROM AUTHOR]

The effects of powder preparation and conditions of hot pressing on the structure and density of consolidated Sm2Fe17Nx and Sm2Fe17Nx/Fe–Co magnets have been studied. Densities achieved in the case of Sm2Fe17Nx powders prepared through a low-energy milling were higher than after a high-energy milling. The difference is mostly caused by the different particle size, and it can be eliminated by an additional low-energy milling of the coarse high-energy milled powder. The presence of a ductile soft magnetic phase greatly facilitates densification, leading to considerably higher absolute and relative densities in hot-pressed Sm2Fe17Nx/Fe0.65Co0.35 composites. We have found that during hot pressing, nitrogenization of the Sm2Fe17 phase may occur in situ if pressed together with Fe–Co–N powders. Because Fe–Co–N releases nitrogen below the decomposition temperature of Sm2Fe17Nx, we were able to fabricate the Sm2Fe17Nx/Fe0.65Co0.35 composite with the density up to 7.6 g/cm3 by hot-pressing mixtures of Sm2Fe17 and (Fe0.65Co0.35)89N11 powders. [ABSTRACT FROM AUTHOR]

The mechanical behavior of surrounding rock mass is key important to the water-sealed petrol storage caverns because of the two phase environment. To investigate the strength and damage mechanism of rock mass under petrol–water immersion circumstance, an elastic–plastic damage constitutive model is proposed. The deformation work of rock mass is derived according to the mixture theory and averaging methods. In order to further study the capillary action influence of petrol–water liquid phase on the strength and stiffness of rock mass, the plastic yield condition considering petrol–water circumstance is proposed. Then, the stress–strain increment expression under the influence of both liquid and solid phase is deduced through the consistency condition. Meanwhile, the damage conditions of the rock mass under tensile and compressive stress differ a lot, so the rock mass damage model under petrol–water circumstance is established combining the tensile and compressive damage criterion and the damage evolution law. The proposed constitutive model is adopted to simulate the mechanical property and damage evolution feature of rock mass under axial compression. The results suggest that the increase in the petrol pressure leads to the improvement of the axial strength for rock mass and meanwhile, the occurrence of damage is also advanced. In addition, the elastic–plastic property of the rock material has been well developed below the stress peak point during this process. Ultimately, the proposed elastic–plastic damage constitutive model was verified by making comparisons between the theoretical calculating results and experimental results. [ABSTRACT FROM AUTHOR]

Ergosterol biosynthesis in Saccharomyces cerevisiae is complex and the underlying mechanism of regulation remains unclear. To clarify the influence of transcriptional regulation on the ergosterol content, transcription factor Ecm22 was overexpressed in S. cerevisiae. Results showed that the overexpression of ECM22 led to an increased invasive growth. Fluconazole susceptibility testing indicated that strains overexpressing ECM22 could grow at 20 μg(fluconazole) ml−1. By contrast, the control failed to grow at 16 μg(fluconazole) ml−1. Among truncated ECM22 fragments, only the 1440‐bp DNA fragment exerted almost the same impact on ergosterol content as that of the full‐length gene. In a 5‐l bioreactor, the highest ergosterol yield of the recombinant reached 32∙7 mg g(dry cell weight)−1, which was increased by about 20% compared with that of the control. In this work, a novel approach for enhancing the ergosterol production by overexpressing a transcription factor in S. cerevisiae was developed. Significance and Impact of the Study: Ergosterol is widely utilized as a raw material for the production of sterol drugs and vitamin D2. Yeast fermentation is an efficient approach to obtain ergosterol at present. In this work, transcription factor Ecm22 was proved to enhance the ergosterol biosynthesis in Saccharomyces cerevisiae. Also, the truncated transcription factors with various activities could be a valuable tool to regulate the intracellular ergosterol level. [ABSTRACT FROM AUTHOR]

An effort to increase the impact toughness of Nd-Fe-B sintered magnets by adding small amounts of Al, Nd, Ga, Cu, and Nb was successful. No significant compromise to magnetic properties occurred. Based on this work, a series of sintered Nd-Fe-B magnets with improved toughness was developed, which we call ToughNEO™. Small precipitates, which may contribute to the improvement of toughness, were observed using scanning electron microscope for all samples with improved toughness. Tumbling and drilling tests further verified the improved toughness of these developed ToughNEO™ magnets. [ABSTRACT FROM AUTHOR]

Castanopsis kawakamii is an endangered tree species due to its low population in the middle stage of development and low percentage of seedlings in natural conditions. The present study explored whether a forest gap has the potential to promote the regeneration of C. kawakamii seedlings, and examined favourable locations for seedling regeneration within the gap. Nine sampling gaps were classified into small, medium and large sizes. The number of C. kawakamii, their basal areas and height at four stages (tree, sapling, shrub and seedling) in five locations within the gap (center, south, east, north and west) were determined during the growing season. A significant positive relationship was found between the number of C. kawakamii and gap area (r = 0.815, p = 0.007), with higher numbers in large gap size (p = 0.031) compared with small gap size. The number of C. kawakamii was predicted by a linear regression model: Number of C. kawakamii = 0.124 × gap area + 10.597, R2 = 0.664. Moreover, the number and size of seedlings in the center of the gap were significantly different (p = 0.041, p = 0.017) from other locations within the gap. Management for C. kawakamii should move forward to provide suitable conditions for regeneration by focusing on the centre and large gap areas. [ABSTRACT FROM AUTHOR]

Microstructural features of a geometrically closed packed hexagonal η-Ni3(Ti, Al) phase precipitated in a long-term-aged Ni-based superalloy are characterised using various kinds of transmission electron microscope (TEM) techniques. The defect features in the η grain interior are clearly revealed at the atomic scale. A nano-sized γ′ phase is found at the defect regions of the micro-sized η phase. The interior γ′ phase keeps a good orientation relationship (OR) of (1 1 1)γ′//(0 0 0 1)η and [1 0]γ′//[2 0]η with the η-Ni3(Ti, Al) phase. However, there is no definitive OR between η-Ni3(Ti, Al) grains and the surrounding matrix. By means of first-principle calculations, we reveal that a symmetrical interfacial feature between γ′ and η corresponds to a lower energy state. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To explore the effects of remote ischemic preconditioning on myocardial injury and prognosis after percutaneous coronary intervention (PCI) in patients with acute coronary syndrome. PATIENTS AND METHODS: The study was a single center, prospective, randomized, controlled study. A total of 184 patients with unstable angina undergoing elective PCI were randomly assigned to remote ischemic preconditioning group (induced by four times of 5-min inflations of a blood pressure cuff to 200 mmHg around the upper arm, followed by 5-min intervals of reperfusion at 1 h before PCI therapy) or control group (an uninflated cuff around the arm). Successful completion of the PCI eventually included 130 cases of patients, including 72 cases in the remote ischemic preconditioning group and 58 cases in the control group. CK-MB, cTnI, sICAM- 1, sVCAM-1 and Hs-CRP levels were measured at 6 am. of the day operating PCI and at 24 h after PCI in the two groups. Major adverse cardiac events were recorded of two groups of patients in the postoperative 6 months. (MACE, including recurrence of angina pectoris, myocardial infarction and death). RESULTS: T here w ere n o s tatistically s ignificant differences in baseline indicators between the 2 groups. CK - MB, cTnI, sICAM-1, sVCAM-1 and Hs-CRP levels in patients with remote ischemic preconditioning group were significantly lower than those form the control group after PCI (p < 0.05), but there were no significant differences between the occurrence of MACE in the postoperative 6 months (p > 0.05). CONCLUSIONS: Remote ischemic preconditioning can reduce PCI related myocardial injury and protect vascular endothelial function. [ABSTRACT FROM AUTHOR]

Many factors have been identified to influence the risk of mother to child transmission (MTCT) of HIV. Chief amongst these is high maternal VL and advanced disease. High maternal viral load (mVL), measured at delivery, has been described as the strongest risk factor for both in utero (IU) and intrapartum (IP) transmission. Similarly, CD4+ T cell count and clinical stage of infection are also the confirmed significant predictors of transmission. Correspondingly, higher mVL in the genital tract has also been independently associated with a higher risk of MTCT of HIV-1. So, the present review article would put light on various aspects of factors responsible for MTCT of HIV in pediatric patients. [ABSTRACT FROM AUTHOR]

Head and neck cancer is one of the most prevalent cancers around the world. Head and neck squamous cell carcinoma (HNSCC) accounts for nearly 90% of head and neck cancer. In recent years, significant advances have been made in immunotherapy for HNSCC. Although some clinical trials targeting immune checkpoints have shown success, the molecular mechanism for regulation of programmed death 1 (PD-1) and its ligand (PD-L1) is partially understood. In an effort to explore the effect of activation of signal transducers and activators of transcriptions (STAT3) on PD-1/PD-L1, the expression and correlation between phosphorylation of STAT3 and PD-1/PD-L1 were determined with immunostaining of human and mouse HNSCC tissue sections. PD-1/PD-L1 overexpression was found to be significantly associated with p-STAT3 in human and mouse HNSCC. Targeting STAT3 by a small molecule effectively inhibited the expression of PD-L1 in the CAL27 cell line. Furthermore, we found that blockade of STAT3 signaling downregulated PD-1/PD-L1 in a Tgfbr1/Pten 2cKO HNSCC mouse model. These findings suggest that STAT3 signaling plays an important role in PD-1/PD-L1 regulation and the antitumor immune response of HNSCC. [ABSTRACT FROM AUTHOR]

A strong laser field (≈ 1015 W/cm²) induced low-collisional-energy charge transfer process in Ne+-He system is explored. In the low collisional energy regime, the cross-section can be ≈ 10-17 cm² which is about two orders of magnitude higher than the collision-only process. With increasing collisional energy the cross-section curve displays flattens and the charge capture tends to be practically independent of the laser detuning. In addition, we find that the capture probability in this Ne+-He system varies significantly with the laser polarization angle. [ABSTRACT FROM AUTHOR]

Based on first-principles calculations, we report that external pressure can induce a topological phase transition in alkaline-earth hexaborides, XB6 (X = Ca, Sr, and Ba). It was revealed that XB6 are transformed from trivial semiconductors to topological node-line semimetals under moderate pressure when the spin–orbit coupling (SOC) is ignored. The band inversion between the B p-orbitals at the X point is responsible for the formation of node-line semimetals. Three node-line rings around the X point are protected by the combination of the time-reversal and spatial inversion symmetries, and drumhead surface bands are obtained in the interiors of the projected node-line rings. When the SOC is included, tiny gaps (＜4.8 meV) open at the crossing lines and the XB6 become strong topological insulators with Z2 indices (1 : 111). As the SOC-induced gap opening is negligible, our findings thus suggest ideal real systems for experimental exploration of the fundamental physics of topological node-line semimetals. [ABSTRACT FROM AUTHOR]