The Development of Spheroidal Grains and Thixoforming of AZ91D Magnesium Alloy Treated by Different Routes

A new process squeeze casting-solid extrusion was introduced to prepare semi-solid billets for thixoforging together with partial remelting. The microstructure development and tensile properties of AZ91D alloy reheated from states of as-cast and SCSE-formed were researched. During partial remelting, samples from SCSE-formed obtained finer and more uniform microstructure obviously than from as-cast. As the holding time went on, both solid particles from the two states experienced continuous spheroidization, and in the meantime from SCSE-formed were always to coarsen, while from as-cast were refined initially and coarsened then. Microstructure development is determined by the combination effects of various factors, including distortion energy from SCSE deformation, grain coalescence, Ostwald ripening mechanism, etc. During thixoforging, components with good forming quality were prepared successfully. Excellent tensile properties were obtained for the thixoforged alloy prepared by SCSE deformation, mainly with the microstructure refinement and the decrease of defects related. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6482</p

The Bile Acid Membrane Receptor TGR5 in Cancer: Friend or Foe?

The G-protein-coupled bile acid receptor, Gpbar1 or TGR5, is characterized as a membrane receptor specifically activated by bile acids. A series of evidence shows that TGR5 induces protein kinase B (AKT), nuclear factor kappa-B (NF-&kappa;B), extracellular regulated protein kinases (ERK1/2), signal transducer and activator of transcription 3 (STAT3), cyclic adenosine monophosphate (cAMP), Ras homolog family member A (RhoA), exchange protein activated by cAMP (Epac), and transient receptor potential ankyrin subtype 1 protein (TRPA1) signaling pathways, thereby regulating proliferation, inflammation, adhesion, migration, insulin release, muscle relaxation, and cancer development. TGR5 is widely distributed in the brain, lung, heart, liver, spleen, pancreas, kidney, stomach, jejunum, ileum, colon, brown adipose tissue (BAT), white adipose tissue (WAT), and skeletal muscle. Several recent studies have demonstrated that TGR5 exerts inconsistent effects in different cancer cells upon activating via TGR5 agonists, such as INT-777, ursodeoxycholic acid (UDCA), and taurolithocholic acid (TLCA). In this review, we discuss both the &lsquo;friend&rsquo; and &lsquo;foe&rsquo; features of TGR5 by summarizing its tumor-suppressing and oncogenic functions and mechanisms

Characterization of the complete chloroplast genome of Lonicera tangutica (Caprifoliaceae), an ornamental and medicinal plant in China

In the present study, the complete chloroplast genome of Lonicera tangutica is presented and characterized for the first time. The complete chloroplast genome was 156,121 bp in length, including 23,899 bp inverted repeat (IR) regions, an 89,466 bp large single-copy (LSC) region, and an 18,851 bp small single-copy (SSC) region. A total of 129 genes, including 37 tRNA genes, eight rRNA genes, and 84 protein-coding genes, were annotated, and the overall GC content of the chloroplast genome was 38.35%. Two introns in the ycf3 gene and a single intron in another gene were detected. Maximum-likelihood phylogenetic analysis indicated that L. tangutica has a very close evolutionary relationship with Lonicera praeflorens, Lonicera hispida, Lonicera fragrantissima, and Lonicera stephanocarpa. These results are valuable for studying the evolution and genetic diversity of L. tangutica

Elucidating the Molecular Mechanisms by which Seed-Borne Endophytic Fungi, <em>Epichloë gansuensis</em>, Increases the Tolerance of <em>Achnatherum inebrians</em> to NaCl Stress

Seed-borne endophyte Epichloë gansuensis enhance NaCl tolerance in Achnatherum inebrians and increase its biomass. However, the molecular mechanism by which E. gansuensis increases the tolerance of host grasses to NaCl stress is unclear. Hence, we firstly explored the full-length transcriptome information of A. inebrians by PacBio RS II. In this work, we obtained 738,588 full-length non-chimeric reads, 36,105 transcript sequences and 27,202 complete CDSs from A. inebrians. We identified 3558 transcription factors (TFs), 15,945 simple sequence repeats and 963 long non-coding RNAs of A. inebrians. The present results show that 2464 and 1817 genes were differentially expressed by E. gansuensis in the leaves of E+ and E− plants at 0 mM and 200 mM NaCl concentrations, respectively. In addition, NaCl stress significantly regulated 4919 DEGs and 502 DEGs in the leaves of E+ and E− plants, respectively. Transcripts associated with photosynthesis, plant hormone signal transduction, amino acids metabolism, flavonoid biosynthetic process and WRKY TFs were differentially expressed by E. gansuensis; importantly, E. gansuensis up-regulated biology processes (brassinosteroid biosynthesis, oxidation–reduction, cellular calcium ion homeostasis, carotene biosynthesis, positive regulation of proteasomal ubiquitin-dependent protein catabolism and proanthocyanidin biosynthesis) of host grass under NaCl stress, which indicated an increase in the ability of host grasses’ adaptation to NaCl stress. In conclusion, our study demonstrates the molecular mechanism for E. gansuensis to increase the tolerance to salt stress in the host, which provides a theoretical basis for the molecular breed to create salt-tolerant forage with endophytes

Pt Nanoparticle–Mn Single-Atom Pairs for Enhanced Oxygen Reduction

The intrinsic roadblocks for designing promising Pt-based oxygen reduction reaction (ORR) catalysts emanate from the strong scaling relationship and activity–stability–cost trade-offs. Here, a carbon-supported Pt nanoparticle and a Mn single atom (PtNP–MnSA/C) as in situ constructed PtNP–MnSA pairs are demonstrated to be an efficient catalyst to circumvent the above seesaws with only ∼4 wt % Pt loadings. Experimental and theoretical investigations suggest that MnSA functions not only as the “assist” for Pt sites to cooperatively facilitate the dissociation of O2 due to the strong electronic polarization, affording the dissociative pathway with reduced H2O2 production, but also as an electronic structure “modulator” to downshift the d-band center of Pt sites, alleviating the overbinding of oxygen-containing intermediates. More importantly, MnSA also serves as a “stabilizer” to endow PtNP–MnSA/C with excellent structural stability and low Fenton-like reactivity, resisting the fast demetalation of metal sites. As a result, PtNPs–MnSA/C shows promising ORR performance with a half-wave potential of 0.93 V vs reversible hydrogen electrode and a high mass activity of 1.77 A/mgPt at 0.9 V in acid media, which is 19 times higher than that of commercial Pt/C and only declines by 5% after 80,000 potential cycles. Specifically, PtNPs–MnSA/C reaches a power density of 1214 mW/cm2 at 2.87 A/cm2 in an H2–O2 fuel cell

Pt Nanoparticle–Mn Single-Atom Pairs for Enhanced Oxygen Reduction

The intrinsic roadblocks for designing promising Pt-based oxygen reduction reaction (ORR) catalysts emanate from the strong scaling relationship and activity–stability–cost trade-offs. Here, a carbon-supported Pt nanoparticle and a Mn single atom (PtNP–MnSA/C) as in situ constructed PtNP–MnSA pairs are demonstrated to be an efficient catalyst to circumvent the above seesaws with only ∼4 wt % Pt loadings. Experimental and theoretical investigations suggest that MnSA functions not only as the “assist” for Pt sites to cooperatively facilitate the dissociation of O2 due to the strong electronic polarization, affording the dissociative pathway with reduced H2O2 production, but also as an electronic structure “modulator” to downshift the d-band center of Pt sites, alleviating the overbinding of oxygen-containing intermediates. More importantly, MnSA also serves as a “stabilizer” to endow PtNP–MnSA/C with excellent structural stability and low Fenton-like reactivity, resisting the fast demetalation of metal sites. As a result, PtNPs–MnSA/C shows promising ORR performance with a half-wave potential of 0.93 V vs reversible hydrogen electrode and a high mass activity of 1.77 A/mgPt at 0.9 V in acid media, which is 19 times higher than that of commercial Pt/C and only declines by 5% after 80,000 potential cycles. Specifically, PtNPs–MnSA/C reaches a power density of 1214 mW/cm2 at 2.87 A/cm2 in an H2–O2 fuel cell