The enhancer of zeste homolog 2 (EZH2) is upregulated and has an oncogenic role in several types of human cancer. However, the abnormalities of EZH2 and its underlying mechanisms in the pathogenesis ...of nasopharyngeal carcinoma (NPC) remain unknown. In this study, we found that high expression of EZH2 in NPC was associated closely with an aggressive and/or poor prognostic phenotype (P<0.05). In NPC cell lines, knockdown of EZH2 by short hairpin RNA was sufficient to inhibit cell invasiveness/metastasis both in vitro and in vivo, whereas ectopic overexpression of EZH2 supported NPC cell invasive capacity with a decreased expression of E-cadherin. In addition, ablation of endogenous Snail in NPC cells virtually totally prevented the repressive activity of EZH2 to E-cadherin, indicating that Snail might be a predominant mediator of EZH2 to suppress E-cadherin. Furthermore, co-immunoprecipitation (IP), chromatin IP and luciferase reporter assays demonstrated that in NPC cells, (1) EZH2 interacted with HDAC1/HDAC2 and Snail to form a repressive complex; (2) these components interact in a linear fashion, not in a triangular fashion, that is, HDAC1 or HDAC2 bridge the interaction between EZH2 and Snail; and (3) the EZH2/HDAC1/2/Snail complex could closely bind to the E-cadherin promoter by Snail, but not YY1, to repress E-cadherin. The data provided in this report suggest a critical role of EZH2 in the control of cell invasion and/or metastasis by forming a co-repressor complex with HDAC1/HDAC2/Snail to repress E-cadherin, an activity that might be responsible, at least in part, for the development and/or progression of human NPCs.
As present trends in economic and population growth continue, the natural environment is increasingly being stressed. More and more researchers, institutes and programmes have paid attention to ...product-service systems (PSSes) in the last decade because PSS integrates tangible artefact and intangible service to achieve sustainability, improve enterprise competitiveness, and meet customer needs better. In order to respond to the industrial trend towards PSS and frame the related research, the state-of-the-art of PSS research and development are reported. Furthermore, in order to integrate fragmental PSS solutions, this paper proposes a framework for product-service lifecycle management (PSLM) and technologies of PSS development. So, four categories are focused on: review of PSS, research about PSS development, a framework for PSLM, and technologies for PSLM (modular product-service development and ontology-based product-service knowledge expression and reuse). The preliminary solution of the implementation roadmap and technologies for PSLM which need to be perfected is proposed to lay a basis for further development and application of PSS for the benefit of industries.
Atomic mobilities of both Co and Si in all the solid phases of the Co–Si system were obtained through assessments of experimentally determined diffusion coefficients from the present work and the ...literature by the DICTRA (diffusion-controlled transformations) simulation package. The first-principles calculations were performed to clarify the contradictory impurity diffusion coefficients of Co in Si by determining the diffusion activation energy. The concept of “average thermodynamic factor” was extended to model binary compounds with certain homogeneity ranges. Based on the atomic mobilities obtained, the diffusion growths of the compounds in wide temperature ranges were predicted. Comprehensive comparisons show that most of the experimental data resulting from diffusion phenomena are well reproduced by the parameters obtained. The approach is of general validity and applicable to establish mobility databases of technically important alloys.
Twenty-six avian infectious bronchitis (IB) viruses (IBV) were isolated from outbreaks in chickens in China between 1995 and 2004. They were characterized by comparison with twenty-six Chinese ...reference strains and five other IBV strains. Chinese IBVs, which were mainly nephropathogenic, were placed into seven genotypes. Fourteen Chinese IBV isolates were placed in genotype I, having small evolutionary distances from each other. Genotype II included 6 strains that were isolated in the 1990s in China. Genotype III consisted of eight Chinese isolates that showed close relationship with Korean IBV isolates. Another eight IBV isolates clustered in genotype IV and showed larger evolutionary distances. The Massachusetts serotype was present in China in 1990s and was in a separate genotype. Two isolates, HN99 and CK/CH/LHN/00I, which might be a reisolation of vaccine strains, clustered into genotype VI. Four Chinese IBV isolates formed another genotype and showed larger evolutionary distances from other Chinese IBV genotypes (genotype VII). IBVs in same genotypes showed more than 90% amino acid sequence similarities, whereas most of the viruses in different genotypes showed less than 90%. The results showed that IBVs in China came from genetic changes both in IBV populations that existed before the advent of vaccination and in the viruses that were introduced through live vaccines. IBVs showing various genetic differences are cocirculating in China.
The LacLM β-galactosidase of Lactobacillus fermentum K4 is encoded by 2 consecutive genes, lacL (large subunit) and lacM (small subunit), that share 17 overlapping nucleotides. Phylogenetic analysis ...revealed that this enzyme was closely related to other Lactobacillus β-galactosidases and provided significant insight into its common and distinct characteristics. We cloned both the lacL and lacM genes of L. fermentum K4 and heterologously expressed each in Escherichia coli, although the recombinant enzyme was only functional when both were expressed on the same plasmid. We evaluated the enzymatic properties of this species-specific LacLM β-galactosidase and discovered that it acts as both a hydrolase, bioconverting lactose into glucose and galactose, and a transgalactosylase, generating prebiotic galacto-oligosaccharides (GOS). The recombinant β-galactosidase showed a broad pH optimum and stability around neutral pH. The optimal temperature and Michaelis constant (Km) for the substrates o-nitrophenyl-β-d-galactopyranoside and lactose were, respectively, 40°C and 45 to 50°C and 1.31mM and 27mM. The enzyme activity was stimulated by some cations such as Na+, K+, and Mg2+. In addition, activity was also enhanced by ethanol (15%, wt/vol). The transgalactosylation activity of L. fermentum K4 β-galactosidase effectively and rapidly generated GOS, up to 37% of the total sugars from the reaction. Collectively, our results suggested that the β-galactosidase from L. fermentum K4 could be exploited for the formation of GOS.
It is of great significance in the design and evaluation of anti-impact protective structures to investigate the dynamic mechanical properties of lightweight concrete structures. The present work ...aims to address this challenging task by the development of an improved large-diameter split Hopkinson pressure bar that can accurately predict the dynamic compressive strength and impact failure characteristics of lightweight concrete under different stress states. Our findings exposed that the impact resistance of lightweight concrete is substantially improved and the failure modes of it have altered under the 3D coupled static–dynamic loads. When the confining pressure remains at the same level and the loading strain rate is low, the unloading curve of lightweight concrete shows a significant hysteresis phenomenon. We have further found that for a higher strain rate the stress–strain curve can be divided into five stages: (i) the inertial-effect-enhanced stage, (ii) the nonlinear elastic deformation stage, (iii) the elastoplastic deformation stage, (iv) the strain-softening stage, and (v) the plastic flow stage. Based on the linear relationships among the logarithm of the strain rate, the dynamic increase factor (DIF), and the confining pressure conditions, we have constructed a two-factor equation for the DIF of lightweight concrete that depends on the confining pressure and the strain rate.
We have studied the structure and the photoluminescence of Mn-passivated nanocrystalline ZnO thin films. The ZnO thin films were prepared by thermally oxidizing ZnS:Mn films grown by low-pressure ...metalorganic chemical vapor deposition. The structural properties of the ZnO films were examined by X-ray diffraction and X-ray photoelectron spectroscopy. It was demonstrated that the Mn passivation could dramatically change the emission characteristics of nanocrystalline ZnO thin films. The photoluminescence spectra of the films with an optimized Mn-doped concentration showed only ultraviolet emission, while the green emission was fully quenched due to the Mn passivation of the ZnO nanocrystallite surface. A core-shell structure model of the surface passivation is presented. The note of the oxygen vacancy (Vo**) as the dominant recombination center for green emission is discussed.
A millimeter-wave high-power handling capacity circularly polarized shared-aperture transceiver reflectarray antenna is proposed and designed. The short helical reflection antenna is proposed to be ...the reflectarray element. The 360° phase shift can be achieved by rotating the helical element. A flat-top shaped beam shared-aperture transceiver array antenna feed is designed to improve the efficiency and power capacity of the reflectarray antenna. The reflectarray with the aperture size of 49.5 × 49.5 mm2 is designed and simulated. The full-wave simulation results show that at center frequency of 30 GHz, the gain of the antenna is 22.5 dB with the efficiency of 57.8%, and the axis ratio is 0.8 dB. In the range of 26 to 34 GHz, the reflection coefficient is lower than -17.8 dB, with the relative bandwidth of 26.7%. The 1-dB gain bandwidth is 19.4%. Under air condition, the power capacity of the element antenna is 898 W, and the power capacity of the reflectarray antenna is 19.2 kW.
There is currently no particularly effective strategy for patients with persistent atrial fibrillation accompanying heart failure with preserved ejection fraction (HFpEF), especially with recurrent ...atrial fibrillation after ablation. In this study, we will evaluate a new treatment strategy for patients with persistent atrial fibrillation who had at least two attempts (≧2 times) of radio-frequency catheter ablation but experienced recurrence, and physiologic conduction was reconstructed after atrioventricular node ablation or drug therapy, to control the patient's ventricular rate to maintain a regular heart rhythm, which is called His-Purkinje conduction system pacing (HPCSP) with atrioventricular node ablation.
This investigator-initiated, multicenter prospective randomized controlled trial aimed to recruit 296 randomized HFpEF patients with recurrent atrial fibrillation. All the enrolled patients were randomly assigned to the pacing group or the drug treatment group. The primary endpoint is differences in cardiovascular events and clinical composite endpoints (all-cause mortality) between patients in the HPCSP and drug-treated groups. Secondary endpoints included heart failure hospitalization, exercise capacity assessed by cardiopulmonary exercise tests, quality of life, echocardiogram parameters, 6-minute walk distance, NT-ProBNP, daily patient activity levels, and heart failure management report recorded by the CIED. It is planned to compete recruitment by the end of 2023 and report in 2025.
The study aims to determine whether His-Purkinje conduction system pacing with atrioventricular node ablation can better improve patients' symptoms and quality of life, postpone the progression of heart failure, and reduce the rate of rehospitalization and mortality of patients with heart failure.
ChiCTR1900027723, URL: http://www.chictr.org.cn/edit.aspx?pid=46128&htm=4.
Using angle-resolved photoemission spectroscopy, we studied the evolution of electronic structure of NaFe sub(1-x)Co sub(x)As from an optimally doped superconducting compound (x = 0.028) to a heavily ...overdoped nonsuperconducting one (x = 0.109). As in "122"-type iron pnictides, our data suggest that the Co dopant in NaFe sub(1-x)Co sub(x)As supplies extra charge carriers and shifts the Fermi level accordingly. The overall band renormalization remains basically the same throughout the doping range we studied, suggesting that the local magnetic and electronic correlations are not affected by carrier doping. In the x = 0.109 compound, the holelike bands around the zone center Gamma move to deeper binding energies and an electron pocket appears instead, resulting in a Fermi surface topology similar to that of A sub(x)Fe sub(2-y)Se sub(2) (A = K, Cs, Rb, Tl). Our data suggest that a balance between itinerant properties of mobile carriers and local interactions plays an important role for the superconductivity in these materials.
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