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FTL10 is an early flowering mutant of OsFTL10-suppressed transgenic rice (Oryza sativa L.) with premature senescence phenotype. Early leaf senescence can cause negative effects on rice yield, therefore delaying leaf senescence and prolonging the leaf functional stage is one of the important approaches to increase the rice yield. It is well known that ascorbic acid (AsA) is involved in regulating plant growth. To explore the effect of AsA on leaf senescence of FTL10, we treated rice leaves with 0.28 mM AsA. Results showed that total antioxidant capacity was higher and reactive oxygen species were lower in the AsA-treated group. The expression of senescence-associated genes was higher in the control group. Exogenous AsA can stabilize chlorophyll and Rubisco protein contents, delay leaf senescence, and maintain net photosynthetic rate (PN) of rice leaves. Our results suggest that exogenous application of AsA can delay leaf senescence, increase PN, and then increase the rice yield. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The aim of this study was to investigate the effect of propofol (PPF) on myocardial ischemia-reperfusion injury (MIRI) by inhibiting the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway, and to explore the possible underlying mechanism. MATERIALS AND METHODS: A total of 60 Sprague-Dawley (SD) rats were randomly divided into 5 groups, including the Sham group (n=12), the MIRI model group (n=12), the PPF pretreatment group (n=12), the RG81640-CH (RG) pretreatment group (n=12) and the PPF+RG pretreatment group (n=12). The hemodynamic parameters of rats in each group were measured. Serum samples were collected from rats in each group. Meanwhile, the levels of lactate dehydrogenase (LDH), creatine kinase-muscle/ brain (CK-MB), nicotinamide adenine dinucleotide+ (NAD+) and inflammatory factors, including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and monocyte chemotactic protein (MCP), were detected by enzyme-linked immunosorbent assay (ELISA). Myocardial infarction area of rats in each group was detected via 2,3,5-triphenyl tetrazolium chloride (TTC) staining. Moreover, the JAK/STAT pathway, as well as apoptosis indexes in myocardial cells of rats, were detected via Western blotting. RESULTS: Compared with the Sham group, the contents of LDH, CK-MB, NAD+ and inflammatory factors, as well as the area of myocardial infarction were significantly increased in the MIRI group (p<0.05). In terms of hemodynamic parameters, the left ventricular end-diastolic pressure (LVEDP) was significantly increased in the MIRI group. However, heart rate (HR), left ventricular developed pressure (LVDP) and maximal rate of the increase/decrease of left ventricular pressure (±dp/dtmax) were significantly decreased in the MIRI group when compared with those of the Sham group (p<0.05). Compared with the MIRI group, the contents of LDH, CK-MB, NAD+ and inflammatory factors, as well as the area of myocardial infarction and LVEDP were significantly declined in the PPF group. Meanwhile, HR, LVDP and ±dp/dtmax were remarkably increased (p<0.05). No significant differences in each index were found between the PPF + RG group and the MIRI group (p>0.05). Western blotting revealed that the protein level of B-cell lymphoma-2 (Bcl-2) was remarkably increased, while the activity of Caspase-3 was decreased in the PPF group when compared with the MIRI group (p<0.05). In addition, the protein expression levels of JAK1, STAT1 and STAT3 in the PPF group were significantly decreased than those of the MIRI group (p<0.05). However, completely opposite trends were found in the RG group. CONCLUSIONS: PPF reduces the release of inflammatory factors and alleviates tissue damage caused by myocardial apoptosis in MIRI rats by inhibiting the activation of the JAK/STAT pathway. Our findings indicate that PPF has a certain myocardial protective effect on MIRI. [ABSTRACT FROM AUTHOR]

Stellite 3 is an excellent wear-resistant material owing to its high carbon content, but has the serious problem of cracking during laser processing due to its extreme brittleness. To solve this problem a novel composite Stellite alloy which has comparable hardness and sliding wear resistance to Stellite 3 was prepared on 316 stainless steel by laser cladding using a mixed powder of major Stellite 3 and minor Stellite 21. The microstructure and phase of the new alloy was analysed by using a scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The hardness, wear resistance and single-tip scratching behavior of the specimens were investigated experimentally. The results showed that no pores and cracks were formed in the new Stellite alloy laser clad layer. The main reinforcement phases in the microstructure consist of (Co,W)3C, Cr23C6, Cr7C3, Co3Mo. The hardness and wear resistance were improved not only by the carbides, but also by the Co3Mo in this new Stellite alloy. The butterfly valve switch test demonstrated that the sealing properties of the new alloy were significantly better than the existing Stellite 6 alloy. [ABSTRACT FROM AUTHOR]

Martensitic steels used for ball mill liners were prepared. The effect of tempering on the microstructures, Rockwell hardness, and impact toughness of the tested steels was evaluated at room temperature. The fracture morphologies were observed by using metallurgical microscopy, scanning electron microscopy and energy-dispersive spectroscopy. The results showed that tempering decreased the Rockwell hardness and significantly improved the impact toughness of the tested steel. However, the impact toughness of the tempered steels was unstable. Fracture of the tested steel before tempering was quasi-cleavage fracture; however, it changed to ductile and quasi-cleavage fracture after tempering. Carbide segregations formed at the local grain boundaries became the crack source and were the preferred ways for crack propagation during the impact test. The existence of segregations was inferred to be the main reason for the fluctuation of impact toughness. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To investigate the expression levels of T follicular helper (Tfh) with different subsets in patients with rheumatoid arthritis (RA) and their serum interleukin-6 (IL-6), interleukin-17 (IL-17), transforming growth factor- β (TGF-β) and matrix metalloproteinase 3 (MMP-3) contents. PATIENTS AND METHODS: The medical records of 45 RA patients in the Department of Rheumatology and Immunology in the First Affiliated Hospital of Chengdu Medical College from January 2016 to April 2018 were retrospectively analyzed. They were divided into the RA high activity group (24 cases, group A) (DAS28 score ≥ 5.0) and RA low activity group (21 cases, group B) (3.2 < DAS28 score < 5.0). At the same time, 20 healthy subjects were selected as a control group. Flow cytometry was used to detect the expression levels of Tfh1, Tfh2 and Tfh17, enzyme- linked immunosorbent assay to detect serum IL-6, IL-17, TGF-β and MMP-3 concentrations. The correlation of Tfh cells with IL-6, IL- 17, TGF-β and MMP-3 was analyzed. RESULTS: Those of peripheral blood mononuclear cell (PBMC) Tfh2 and Tfh17 cells were significantly higher in group A than those in group B (p < 0.05). Compared with the control group, the concentrations of serum IL-6, IL-17 and MMP-3 significantly increased (p < 0.001), but that of serum TGF-β markedly decreased in group A and group B (p < 0.01). The concentrations of serum IL-6, IL-17 and MMP-3 were remarkably higher in group A than those in group B (p < 0.001), but that of serum TGF-β was significantly lower in group A than that in group B (p < 0.001). The expression level of PBMC Tfh2 cells, PBMC Tfh17 cells was positively correlated with serum IL-6, IL-17 and MMP-3. The expression levels of Tfh2 and Tfh17 cells are positively correlated with serum IL-6, IL-17 and MMP- 3 concentrations, negatively correlated with serum TGF-β concentration. CONCLUSIONS: Tfh2 and Tfh17 are expected to be new targets for immunotherapy in RA patients. [ABSTRACT FROM AUTHOR]

Laser photofragmentation of Si, Ge, and GaAs positive cluster ions prepared by laser vaporization and supersonic beam expansion has been investigated using tandem time-of-flight mass spectrometry. Si clusters up to size 80, Ge clusters to size 40, and GaAs clusters up to a total of 31 atoms were studied. Si+n and Ge+n for n=12–26 give daughter ions of about half their original size. For both Si and Ge, this apparent positive ion fissioning appears to go over with increasing n to neutral loss of seven and ten, but for Si+n the range of n values where this is observed is rather small. At low fluences, the larger Ge+n clusters up to the maximum size observed (50) sequentially lose Ge10 (and in some cases with lower intensity Ge7). Larger Si+n clusters (n>30) always fragment primarily to produce positive ion clusters in the 6–11 size range with a subsidiary channel of loss of a single Si atom. At high laser fluences, Ge+n also fragments to produce primarily positive ion clusters in the 6–11 size range with an intensity pattern essentially identical to Si+n at similar fluences. GaxAs+y clusters lose one or more atoms in what is probably a sequential process with positive ion clusters in which the total number of atoms, x+y, is odd being more prominent. [ABSTRACT FROM AUTHOR]

Silicon, germanium, and gallium arsenide negative cluster ions are produced by laser vaporization followed by free supersonic expansion. Electron affinities (EA) of the corresponding neutral clusters are roughly bracketed by measuring the fluence dependence for photodetachment from anions at discrete probe laser wavelengths (above the photodetachment threshold the dependence on fluence is linear, below it is quadratic). An even/odd alternation is found in the negative ion distribution with gallium arsenide clusters with an odd number of atoms having higher EA’s than their even neighbors. This suggests that the surfaces of the even clusters are extensively restructured in a way which eliminates dangling chemical bonds. For GaxAsy with x+y constant, EA increases with increasing ratio of y to x. The EA of silicon increases smoothly with cluster size extrapolating towards the EA of bulk silicon. Photofragmentation studies show that, like the corresponding positive ions, silicon and germanium negative ions with 11 to 23 atoms fission into mainly 5 to 10 atom negative ions. Si-10 and Ge-10 are the favorite daughters suggesting the existence of a special structure for ten atoms. [ABSTRACT FROM AUTHOR]

Summary: This paper reports a second‐order nonautonomous memristive diode bridge‐based circuit, upon which a system model is established. The AC and DC equilibrium points and their stability evolutions are theoretically analyzed, and the mechanisms of complex dynamical behaviors are explored in detail. Furthermore, the stimulus‐dependent dynamical behaviors are numerically performed by the single‐parameter bifurcation diagrams, Lyapunov exponents, and phase portraits. Of particular concern, it should be highly emphasized that multiple kinds of crisis scenarios associated with the initial conditions are found in a specified parameter region, resulting in that coexisting multiple attractors under different initial conditions are discovered for the fixed system parameters. Additionally, hardware experiments and PSpice circuit simulations are used to confirm the numerically simulated results. [ABSTRACT FROM AUTHOR]

Summary: The reliable bonding of W/CuCrZr is facing a great challenge due to their big difference of mechanical properties, especially the mismatch of thermal expansion coefficient. To find out effective ways to enhance the bonding strength of W/CuCrZr, 3 experimental schemes, ie, vacuum diffusion bonding without any interlayer (benchmark scheme), oxygen‐free high thermal conductivity (OFHC) copper foil as the interlayer, and diamond/Cu composite as the interlayer are designed and studied in this paper. It is found that OFHC copper foil can effectively reduce the bonding defects and improve the bonding strength. The average tension strength and shear strength of the specimens are approximately 75 and 190 MPa, respectively. In addition, it is found that diamond/Cu composite is a good choice for strengthening the bonding by completing vacuum sintering of the composite and its diffusion bonding with W and CuCrZr at the same time. The average tension strength of the samples is around 65 MPa, and the average shear strength is approximately 150 MPa with the highest one up to 180 MPa. [ABSTRACT FROM AUTHOR]

Supersonic laser deposition (SLD) is a novel coating method which combines the supersonic powder stream produced by cold spray with synchronous laser heating of the deposition zone. This article presents a study of using the SLD Ni60-Ni composite coatings on a #45 medium carbon steel substrate (AISI 1045). The microstructure of coatings and deposition characteristics were analyzed using scanning electron microscope (SEM) and energy dispersion spectrum (EDS), respectively. The results show that the SLD technique is able to achieve a dense crack-free coating, because deformed Ni particles are evenly distributed in the coatings, which benefit releasing residual stress developed in the composite coatings. The cross-section thickness of the Ni60-Ni composite coatings increased with enhanced laser power. It is also found that a Ni-rich layer is generated at the interface between the coating and substrate. This softer Ni-rich layer serves as a transition layer to accommodate the adhesion between the coating and substrate. [ABSTRACT FROM AUTHOR]

Provides information on a study which measured the band-gap narrowing effect of gallium arsenide as a function of carbon doping concentration using photoluminescence (PL) spectroscopy on samples grown by metalorganic chemical vapor deposition. Range of carbon concetration; Intensity of PL spectra.