10,505 research outputs found

    Effect of the Chinese herb Mesima Reishi UE-1 on invasion of human ovarian cancer cells in vitro

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    To study the effects of Mesima Reishi UE-1 on the metastatic phenotype of the human ovarian cancer cell line HO8910. HO8910 cells were pretreated with different concentration of Mesima Reishi UE-1 in vitro. Using cell proliferation assay, spreading and adhesion assay, cell migration and invasion assay, zymography, immunocytochemical staining and RT-PCR, we examined the effects of Mesima Reishi UE- 1 on cell proliferation, motility, adhesion and expression of MMP-2, 9 in vitro. Mesima Reishi UE-1 directly inhibited HO8910 cell proliferation in vitro. And pretreated with different concentrations of Mesima Reishi UE-1, HO8910 cells motility, adhesion and invasion were inhibited significantly. The activity of MMP-9 was inhibited in a dose-dependent manner. The protein and mRNA expression of MMP-2, 9 were also inhibited. Mesima Reishi UE-1 suppresses invasion of human ovarian cancer cells in vitro.Key words: Mesima Reishi UE-1, polysaccharides, human ovarian cancer, tumor invasion, matrix metalloproteinase

    Directional ordering of fluctuations in a two-dimensional compass model

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    A classical realization of directional coupling in two dimension of the effective orbital-orbital interaction in the Mott insulating phase of the transition metal oxides (TMO) was presented. The model exhibited partial orbital ordering in the form of directional ordering of fluctuation at low temperatures stabilized by an entropy gap. The directional ordering was necessarily accompanied by a lattice distortion and the bond length in horizontal and vertical directions became unequal when the couplings of the orbital isosopin to lattice modes were included. Analysis shows that the compass model has a low temperature phase which exhibited long-ranged correlations in the directions of fluctuations in both isospin and lattice spaces.published_or_final_versio

    Does psychosocial stress impact cognitive reappraisal? Behavioral and neural evidence

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    Cognitive reappraisal (CR) is regarded as an effective emotion regulation strategy. Acute stress, however, is believed to impair the functioning of prefrontal-based neural systems, which could result in lessened effectiveness of CR under stress. This study tested the behavioral and neurobiological impact of acute stress on CR. While undergoing fMRI, adult participants (n = 54) passively viewed or used CR to regulate their response to negative and neutral pictures and provided ratings of their negative affect in response to each picture. Half of the participants experienced an fMRI-adapted acute psychosocial stress manipulation similar to the Trier Social Stress Test, and a contr ol group received parallel manipulations without the stressful components. Relative to the control group, the stress group exhibited heightened stress as indexed by self-report, heart rate, and salivary cortisol throughout the scan. Contrary to our hypothesis, we found that reappraisal success was equivalent in the control and stress groups, as was electrodermal response to the pictures. Heart rate deceleration, a physiological response typically evoked by aversive pictures, was blunted in response to negative pictures and heightened in response to neutral pictures in the stress group. In the brain, we found weak evidence of stress-induced increases of reappraisalrelated activity in parts of the PFC and left amygdala, but these relationships were statistically fragile. Together, these findings suggest that both the self-reported and neural effects of CR may be robust to at least moderate levels of stress, informing theoretical models of stress effects on cognition and emotion

    Single Versus Multi-channel Dispersion Analysis of Ultrasonic Guided Waves Propagating in Long Bones

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    Ultrasonic guided wave techniques have been applied to characterize cortical bone for osteoporosis assessment. Compared with the current gold-standard X-ray-based diagnostic methods, ultrasound-based techniques pose some advantages such as compactness, low cost, lack of ionizing radiation, and their ability to detect the mechanical properties of the cortex. Axial transmission technique with a source-receiver offset is employed to acquire the ultrasound data. The dispersion characteristics of the guided waves in bones are normally analyzed in the transformed domains using the dispersion curves. The transformed domain can be time-frequency map using a single channel or wavenumber-frequency (or phase velocity-frequency) map with multi-channels. In terms of acquisition effort, the first method is more cost- and time-effective than the latter. However, it remains unclear whether single-channel dispersion analysis can provide as much quantitative guided-wave information as the multi-channel analysis. The objective of this study is to compare the two methods using numerically simulated and ex vivo data of a simple bovine bone plate and explore their advantages and disadvantages. Both single- and multi-channel signal processing approaches are implemented using sparsity-constrained optimization algorithms to reinforce the focusing power. While the single-channel data acquisition and processing are much faster than those of the multi-channel, modal identification and analysis of the multi-channel data are straightforward and more convincing

    Characterization and evaluation of Bacillus isolates for their potential plant growth and biocontrol activities against tomato bacterial wilt

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    About 200 Bacillus isolates were isolated from tomato and potato rhizosphere and examined for their antagonistic activities against Ralstonia solanacearum T-91, the causal agent of tomato bacterial wilt (TBW), in vitro and in vivo. Four strains, AM1, D16, D29 and H8, have shown high potential of antagonistic activity against the pathogen in laboratory and greenhouse experiments. In greenhouse, 81.1 to 89.0% reduction of disease incidence of TBW was recorded in treated tomato plants with 4 isolates, which also significantly (p > 0.05) increased plant height by 22.7 to 43.7% and dry weight by 47.93 to 91.55% compared with non-treated control. 16SrRNA gene sequence, the biochemical and physiological tests and fatty acid methyl esters analysis assigned strains AM1 and D29 as Bacillus amyloliquefaciens, while strains D16 and H8 as Bacillus subtilis and B. methylotrophicus, respectively. In addition, the 4 strains showed ability to inhibit growth of the three soil-borne fungi, produce indole-3- acetic acid, siderophores and also with exception of strain D16, the other 3 strains were capable of solubilizing phosphate. Therefore, these results suggest that out of 200 isolates, Bacillus stains AM1, D16, D29 and H8 support good antagonistic activity and could be applied as biocontrol agents against TBW under greenhouse conditions beside their potential to promote tomato plants growth.Key words: Tomato, Ralstonia solanacearum, Bacillus spp, biological control, plant growth promotion activitie

    Wnt2 secreted by tumour fibroblasts promotes tumour progression in oesophageal cancer by activation of the Wnt/β-catenin signalling pathway

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    Objectives: Interaction between neoplastic and stromal cells plays an important role in tumour progression. It was recently found that WNT2 was frequently overexpressed in fibroblasts isolated from tumour tissue tumour fibroblasts (TF) compared with fibroblasts from non-tumour tissue normal fibroblasts in oesophageal squamous cell carcinoma (OSCC). This study aimed to investigate the effect of TF-secreted Wnt2 in OSCC development via the tumour - stroma interaction. Methods: Quantitative PCR, western blotting, immunohistochemistry and immunofluorescence were used to study the expression pattern of Wnt2 and its effect on the Wnt/β-catenin pathway. A Wnt2-secreting system was established in Chinese hamster ovary cells and its conditioned medium was used to study the role of Wnt2 in cell proliferation and invasion. Results: Expression of Wnt2 could only be detected in TF but not in OSCC cancer cell lines. In OSCC tissues, Wnt2 (+) cells were mainly detected in the boundary between stroma and tumour tissue or scattered within tumour tissue. In this study, Wnt2-positive OSCC was defined when five or more Wnt2(+) cells were observed in 2003X microscopy field. Interestingly, Wnt2-positive OSCC (22/51 cases) was significantly associated with lymph node metastases (p=0.001), advanced TNM stage (p=0.001) and disease-specific survival (p<0.0001). Functional study demonstrated that secreted Wnt2 could promote oesophageal cancer cell growth by activating the Wnt/β-catenin signalling pathway and subsequently upregulated cyclin D1 and c-myc expression. Further study found that Wnt2 could enhance cell motility and invasiveness by inducing epithelial-mesenchymal transition. Conclusions: TF-secreted Wnt2 acts as a growth and invasion-promoting factor through activating the canonical Wnt/β-catenin signalling pathway in oesophageal cancer cells.published_or_final_versio

    Macroscopic invisibility cloaking of visible light

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    Invisibility cloaks, which used to be confined to the realm of fiction, have now been turned into a scientific reality thanks to the enabling theoretical tools of transformation optics and conformal mapping. Inspired by those theoretical works, the experimental realization of electromagnetic invisibility cloaks has been reported at various electromagnetic frequencies. All the invisibility cloaks demonstrated thus far, however, have relied on nano- or micro-fabricated artificial composite materials with spatially varying electromagnetic properties, which limit the size of the cloaked region to a few wavelengths. Here, we report the first realization of a macroscopic volumetric invisibility cloak constructed from natural birefringent crystals. The cloak operates at visible frequencies and is capable of hiding, for a specific light polarization, three-dimensional objects of the scale of centimetres and millimetres. Our work opens avenues for future applications with macroscopic cloaking devices

    Mechanism of resonant electron emission from the deprotonated GFP chromophore and its biomimetics

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    The Green Fluorescent Protein (GFP), which is widely used in bioimaging, is known to undergo light-induced redox transformations. Electron transfer is thought to occur resonantly through excited states of its chromophore; however, a detailed understanding of the electron gateway states of the chromophore is still missing. Here, we use photoelectron spectroscopy and high-level quantum chemistry calculations to show that following UV excitation, the ultrafast electron dynamics in the chromophore anion proceeds via an excited shape resonance strongly coupled to the open continuum. The impact of this state is found across the entire 355–315 nm excitation range, from above the first bound–bound transition to below the opening of higher-lying continua. By disentangling the electron dynamics in the photodetachment channels, we provide an important reference for the adiabatic position of the electron gateway state, which is located at 348 nm, and discover the source of the curiously large widths of the photoelectron spectra that have been reported in the literature. By introducing chemical modifications to the GFP chromophore, we show that the detachment threshold and the position of the gateway state, and hence the underlying excited-state dynamics, can be changed systematically. This enables a fine tuning of the intrinsic electron emission properties of the GFP chromophore and has significant implications for its function, suggesting that the biomimetic GFP chromophores are more stable to photooxidation

    Foreign Experience and CEO Compensation

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    This paper investigates the relationship between a CEO’s foreign experience and CEO compensation. Our analysis is based on the constituent firms of the UK FTSE 350 index from 1999 to 2015. We find that foreign CEOs and national CEOs with foreign working experience receive significantly higher levels of total compensation compared to similar UK CEOs without such characteristics. The results are robust to the endogenous CEO selection using propensity score matching methods, as well as other modelling approaches. Our results show that pay premiums are attributable to the specialized foreign expertise and foreign networks of CEOs, which stem from foreign experience rather than broader general managerial skills
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