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Aiming to address the Mo volatilization problem of super-austenitic stainless steel at high temperature, the S31254 steel containing B and rare earth element Y with high oxidation resistance was designed. It was observed that a synergy of B + Y can promote the formation of the dense Cr2O3 layer at 1050 and 1100 °C, making MoO3 layer formation difficult. While the oxide layers of the 0B sample from top to bottom were divided into four layers: Fe-rich oxide layer, MoO3 layer, Cr–Mn–Ni spinel oxide layer, and Cr2O3 layer (loose and porous), thus the undense Cr2O3 layer in the 0B sample can hardly inhibit MoO3 volatilization, especially at 1100 °C. In addition, the synergistic effect of B and Y on the diffusion of Cr to the surface was calculated using first-principles calculations. The results demonstrated that both the addition of B and Y can enhance Cr diffusion to the surface, while Y can specifically promote the combination of Cr and O. Consequently, the combined presence of B and Y exhibits a more favorable synergy for improving the density of the Cr2O3 layer, effectively inhibiting MoO3 formation and volatilization, thereby enhancing the oxidation resistance of S31254. [ABSTRACT FROM AUTHOR]

The development of a heat stabilizer with good thermal stability, plasticizing performance, and migration resistance for polyvinyl chloride (PVC) is still a notable challenge. In this work, two bio-based heat stabilizers, epoxidized cardanol oleate (ECD-OA) and epoxidized cardanol myristate (ECD-MA), were designed and synthesized with different lengths of their alkyl chains and different epoxy contents to provide outstanding compatibility with PVC. After confirming the chemical structures of ECD-OA and ECD-MA by proton nuclear magnetic resonance and Fourier-transform infrared spectroscopy, the thermal stabilizing effects of both epoxidized cardanol esters were compared with those of the traditional CaSt2/ZnSt2 stabilizer and bio-based epoxidized soybean oil. Then, the effects of four different heat stabilizers on the mechanical, thermal, rheological, and optical properties of PVC films were fully studied. The results suggested that the ECD-MA showed the best thermal stability, and the PVC/30DOP/5ECD-MA film did not turn black after 2 h of thermal aging at 200 °C. In addition, the ECD-MA had good compatibility with PVC, and it had a synergistic plasticizing effect, which caused the film to have a high ductility and tensile strength (320.1% and 19.8 MPa, respectively). [ABSTRACT FROM AUTHOR]

Background: 5-Hydroxytryptamine (5-HT) and stem cells marker G-protein-coupled receptor 5 (LGR5) are associate with gastrointestinal inflammation and tumorigenesis. But the relationship between 5-HT and LGR5 is unclear. Objective: To explore the expression and correlation of 5-HT and LGR5 in gastric mucosa of patients with gastritis and gastric cancer (GC). Methods: A total of 41 patients with GC and 98 patients with chronic gastritis were included in this study. The expression of TPH1 mRNA, LGR5 mRNA and β-catenin mRNA in gastric mucosa were explored by Real-time Quantitative polymerase chain reaction (qPCR). 5-HT-positive cells and LGR5-positive cells in gastric mucosa were detected by immunohistochemistry stains. The co-localization of 5-HT and chromogranin A (CgA), 5-HT receptor4 (5-HTR4) and LGR5 were detected by multiplex immunofluorescence. Results: The expression of 5-HT and LGR5 in patients with GC was significantly higher than patients with chronic gastritis (p < 0.05). The positive rate of 5-HT and LGR5 increased sequentially in the patients with non-atrophic gastritis, intestinal metaplasia and GC, which were 18.52%, 35.56% and 75.61% for 5-HT, and 27.78%, 40.91% and 95.12% for LGR5, respectively. The expression of 5-HT and LGR5 was positively correlated in gastritis and GC patients (p < 0.05). Moreover, the expression level of TPH1 mRNA and LGR5 mRNA was also positively correlated in gastritis patients (r = 0.7377, p < 0.001). Besides, 5-HT was partially co-localized with CgA, and 5-HTR4 was co-localized with LGR5 in gastric mucosa. Conclusion: The increase of 5-HT synthesis in gastric mucosa may have an impact on LGR5-positive gastric epithelial stem cells. [ABSTRACT FROM AUTHOR]

The occupation tendencies of Cr, Cu, Mo, Nb, Ni, Ti and V in Fcc-Fe stacking fault containing vacancy were studied by the first principles calculations. The effects of C, N and Nb, Ti co-segregation in the region of vacancy is discussed. The results are as follows: the substitutional elements Cr, Cu, Mo, Ni, Nb, Ti and interstitial elements C, N have no segregation tendency at the stacking fault of Fcc-Fe (111) plane. When the stacking fault contains vacancy, the above elements have the tendency to segregate around the vacancy, and C, N tend to occupy vacancy and their segregation tendency is the stronger than that of substitutional elements. C, N are easily co-segregated with Nb, Ti in the region of vacancy. It is difficult for Mo to aggregate around the carbonitride precipitates, which is conducive to the use of nano-scale carbide and nitride precipitation strengthening in high Mo austenitic steel, and simultaneously improves corrosion resistance. Nb and Ti tend to aggregate around the vacancy where occupied by C, N. [ABSTRACT FROM AUTHOR]

Three bis(phenyl)fluorene-based cardo diamine monomers with different side groups (–CF3, –H, and –CH3) were synthesized and used to synthesize three 6FDA-based polyimides (6FDA-FBPF, 6FDA-BPF, and 6FDA-MBPF). The influence of bis(phenyl)fluorene cardo moiety and different side groups on the glass transition temperature (Tg), thermal stabilities, and chain packing of the synthesized polyimides were systematically studied. The gas permeabilities and selectivities of three bis(phenyl)fluorene-based polyimide membranes were studied and correlated with their fractional free volumes and chain packing conditions. As a result, the obtained polyimides showed promising performance for hydrogen separation. Among the three polyimides, 6FDA-FBPF had the highest gas permeabilities which exhibited H2 permeability of 151.12 Barrer and H2/CH4 selectivity of 62.19. The high gas separation performance of 6FDA-FBPF mainly attributed to the ineffective chain packing via the incorporation of bi(phenyl)fluorene cardo moiety and introduction of bulky CF3 side groups into the polyimide backbones that is favorable to formation hourglass-shaped pores. [ABSTRACT FROM AUTHOR]

Manganese oxide/reduced graphene oxide (MnO2/rGO) hybrid with layered MnO2 nanosheets grow on rGO surfaces have been prepared for microwave absorbing. The hybrid exhibits significantly enhanced microwave absorption properties compared with rGO and MnO2. A maximum reflection loss value can reach − 26.7 dB at 11.04 GHz with the matching thickness of 2.6 mm, and the effective absorption bandwidths exceeding − 10 dB and − 20 dB are 3.6 GHz and 1.06 GHz, respectively. The enhancement in microwave absorption efficiency of MnO2/rGO hybrid is arose from the synergistic effects between lamellar MnO2 and rGO in its unique three-dimensional (3D) architecture, which leads to strong conduction loss and multiple reflections, and further in favour of appropriate impedance matching ratio and good attenuation ability. These fundamental understandings on the property-structure relationship of as-synthesized MnO2/rGO hybrid will prove an efficient approach to the designing and construction of MnO2-based 3D nanostructures for advanced electromagnetic wave absorbing applications. [ABSTRACT FROM AUTHOR]

Shewanella baltica and Acinetobacter are among the predominant spoilage bacteria in refrigerated shrimp (Litopenaeus vannamei). S. baltica are incapable of producing acyl-homoserine lactone (AHL) quorum sensing signals, but can respond to environmental AHLs. In this paper, Acinetobacter was found to produce three AHLs, i.e. N-butanoyl-l-homoserine lactone (C4-HSL), N-(3-oxohexanoyl)-l-homoserine lactone (O-C6-HSL) and N-(3-oxooctanoyl)-l-homoserine lactone (O-C8-HSL), according to thin-layer chromatography using the bioreporter Agrobacterium tumefaciens A136. The agar diffusion and β-galactosidase assays revealed that S. baltica could eavesdrop on these three AHLs from Acinetobacter. Eavesdropping on Acinetobacter AHLs especially C4-HSL was found to boost the growth of S. baltica particularly under nutrient limiting conditions (up to 40-fold increase) in the co-culture experiments. The azocasein assay revealed that S. baltica produced fourfold more extracellular proteases in response to Acinetobacter AHLs. As demonstrated by the biofilm crystal violet staining assay and confocal laser scanning microscopy, eavesdropping also decreased the biofilm-forming capacity of Acinetobacter. By inoculation of S. baltica and Acinetobacter onto surface-sterilized shrimp, eavesdropping was found to endow a growth advantage to S. baltica in vivo, resulting in a 0.5 day shortened shelf life of shrimp according to total volatile basic nitrogen levels and sensory analysis. Overall, the AHL-dependent eavesdropping increased the spoilage potential of S. baltica, providing a fresh perspective on the spoilage process of refrigerated L. vannamei, and this may inspire the development of novel preservation techniques in the future to further reduce post-harvest loss of shrimp. [ABSTRACT FROM AUTHOR]

We devised an atmosphere controlling facility to gain a longer life span for mango. A membrane module made of polyethersulfone/polydimethylsiloxane (PES/PDMS) composite membrane was applied to selectively permeate CO from the gas mixture of the fruit container. To design the membrane separation system, two models were introduced into our mathematical simulations: (1) an equilibrium model giving the optimal membrane area, the compositions of CO and O in the fruit container, feed flow rate and pressures on both the feed and permeate sides of the module, and (2) a dynamic model simulating the change in the gas composition of the fruit container with time. The pressure build-up in the bore side of the hollow fiber was also discussed using the Hagen-Poiseuille equation. The best membrane module configuration was obtained based on the pressure build-up analysis. That was (1) the vacuum pressure should be set at 0.1 bar, (2) the hollow fiber inner diameter should be 0.45 mm, and (3) the vacuum should be applied at both ends of the hollow fiber bore sides. [ABSTRACT FROM AUTHOR]

Ab initio density functional theory (DFT) was employed to study geometric and electronic structure of MgF (110) surface. Three different clean surface models have been considered. The results show that the surface terminated with one-layer F has the smallest relaxation and the lowest surface energy, which indicates this model is the most energetically favorable structure of MgF (110) surface. Furthermore, the electronic properties are also discussed from the point of density of states and charge density. Analysis of electronic structure shows that the band gap of the surface is significantly narrowed with respect to the bulk. The electrons of the surface exhibit strong locality and larger effective mass. [ABSTRACT FROM AUTHOR]

In Mg-Li-Al alloys, θ-phase MgAlLi is a strengthening and metastable phase which is liable to be transformed to the equilibrium phase AlLi on overaging. While the structural details of the θ-phase MgAlLi and the microscopic transformation are still unknown. In this paper, the structure of MgAlLi unit cell was determined through X-ray powder diffraction simulation. Microscopic transformation process of θ-phase MgAlLi was discussed in detail using first principles method. [ABSTRACT FROM AUTHOR]

Studies recorded formate and acetate in a mid-latitude glacier in west China. Relationship of the occurrence of formate and acetate with processes in the biosphere; Average concentration of acetate and formate in the area; Formate to acetate ratio average.

Thermotolerant Bacillus coagulans is considered to be a more promising producer for bio-chemicals, due to its capacity to withstand harsh conditions. Two L-lactate dehydrogenase (LDH) encoding genes (ldhL1 and ldhL2) and one D-LDH encoding gene (ldhD) were annotated from the B. coagulans DSM1 genome. Transcriptional analysis revealed that the expression of ldhL2 was undetectable while the ldhL1 transcription level was much higher than that of ldhD at all growth phases. Deletion of the ldhL2 gene revealed no difference in fermentation profile compared to the wild-type strain, while ldhL1 single deletion or ldhL1ldhL2 double deletion completely blocked L-lactic acid production. Complementation of ldhL1 in the above knockout strains restored fermentation profiles to those observed in the wild-type strain. This study demonstrates ldhL1 is crucial for L-lactic acid production and NADH balance in B. coagulans DSM1 and lays the fundamental for engineering the thermotolerant B. coagulans strain as a platform chemicals producer. [ABSTRACT FROM AUTHOR]