The impact of impurity ions on a pedestal has been investigated in the HL-2A Tokamak, at the Southwestern Institute of Physics, Chengdu, China. Experimental results have clearly shown that during the ...H-mode phase, an electromagnetic turbulence was excited in the edge plasma region, where the impurity ions exhibited a peaked profile. It has been found that double impurity critical gradients are responsible for triggering the turbulence. Strong stiffness of the impurity profile has been observed during cyclic transitions between the I-phase and H-mode regime. The results suggest that the underlying physics of the self-regulated edge impurity profile offers the possibility for an active control of the pedestal dynamics via pedestal turbulence.
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Properties of substoichiometric tungsten oxide (WO3-x) semiconducting nanomaterials in diverse applications are morphology-dependent. However, it remains challenging to control morphology and ...structure of WO3-x nanomaterials. Here, we report the solvothermal synthesis of WO3-x nanostructures with different morphologies in tungsten hexachloride-ethanol solution through adjusting the filling fraction of ethanol in autoclave. The structural and morphological conversion mechanisms are related to the changes in the viscosity and Brownian motion caused by the concentration of tungsten hexachloride in ethanol. The studies on the photoluminescence (PL) properties reveal that the WO3-x nanostructures emit ultraviolet, blue, green and red emissions. The PL emissions are attributed to the recombination between the electron occupying the resonant defect state in the conduction band and the hole in the valence band and the transitions between the conduction and valence bands as well as the transition between the oxygen vacancy states. The enhancement of PL intensity is related to the increase of oxygen vacancies and the phonon suppression during the PL emission as well as the nanocavity structure. Furthermore, the potential applications in the catalysis fields are discussed. These results provide a new technique to control the structure of WO3-x nanomaterials and contribute to the development of next-generation PL emission nanodevices based on vacancy- and structure-engineered WO3 materials and the rational design of catalytic materials.
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•Resolving challenging structural conversion of substoichiometric WO3-x nanomaterials.•Coversion mechanisms of WO3-x nanostructures related to the viscosity of solution.•Oxygen-vacancy-engineered WO3-x nanostructures with tunable PL emission.•Advancement of optical properties of WO3-x nanostructures.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract This paper studied through-thickness gradient microstructure of an 80mm ultra-heavy steel plate by multi-dimensional characterizations, meanwhile the cause of microstructure variability as ...well as its effect on strength was analyzed. Results show major lath-structure in the whole steel plate, while lath morphology and grain boundary distribution are different along the thickness direction. During phase transformation, the higher cooling rate in the surface enhances the forming ability of V1/V4 variant pairs and corresponding 5°-10° boundaries, meanwhile the higher cooling rate and smaller original austenite grain contribute to more nucleation sites and stronger strain incompatibility, which is corresponding to more low-angle boundaries, so the surface layer shows higher low-angle boundaries; Compared with the surface layer, the moderate cooling rate is beneficial for V1/V2 variant pairs, and Σ3 boundaries between the pairs are obtained, leading to higher high-angle boundary density with decreased low-angle grain boundary density. This boundary characteristic corresponds to the thinner and longer lath morphology. With respect to the relationship between mechanical properties and microstructure, more low-angle boundaries in the surface layer and more high-angle boundaries in inner layers contribute to stronger dislocation strengthening and grain boundary strengthening respectively, and realizes the coordinated through-thickness property.
Aim
Perineal wound complications after abdominoperineal resection (APR) have become a major clinical challenge. Myocutaneous flap closure has been proposed in place of primary closure to improve ...wound healing. We conducted this comprehensive meta‐analysis to evaluate the current scientific evidence of primary closure vs myocutaneous flap closure of perineal defects following APR for colorectal disease.
Methods
We systematically searched the MEDLINE, Embase, PubMed, Web of Science and Cochrane Library databases to identify all relevant studies. After data extraction from the included studies, meta‐analysis was performed to compare perioperative outcomes of primary closure and myocutaneous flap closure.
Results
Eighteen studies with a total of 17 913 patients (16 346 primary closure vs 1567 myocutaneous flap closure) were included. We found that primary closure was significantly associated with higher total perineal wound complications (P = 0.007), major perineal wound complications (P < 0.001) and perineal wound infection (P = 0.001). On the other hand, myocutaneous flap closure takes more operation time (P < 0.001) and increases the risk of perineal wound dehiscence (P = 0.01), deep surgical site infection (P < 0.001), enterocutaneous fistulas (P = 0.03) and return to the operating room (P = 0.0005). There were no significant differences between the two groups for other outcomes.
Conclusions
This is the first systematic review with meta‐analysis comparing primary closure with myocutaneous flap closure of perineal defects after APR for colorectal disease. Although taking more operation time and an increased risk of specific complications, the pooled results have validated the use of myocutaneous flaps for reducing total/major perineal wound complications. More investigations are needed to draw definitive conclusions on this dilemma.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Proteomic analysis of exosomes from human plasma faces a tremendous challenge mainly due to the low abundance of the exosome itself and the complexity of the plasma matrix. Therefore, enrichment of ...exosomes from human plasma is an essential and indispensable step for large scale and in depth proteomic analysis. Size exclusion chromatography (SEC) is one of the most extensively used methods for exosome isolation from human plasma and many SEC-based tandem methods were established in order to increase the purity of the enriched exosomes and thus the accuracy of the proteomic analysis. To compare the advantages and disadvantages of the different isolation methods and subsequently to promote the establishment of a standardized method for plasma proteomic research, the capacities of the direct SEC method, the combination of SEC with ultracentrifugation (SEC-UC), ultrafiltration (SEC-UF), and titanium dioxide microspheres (SEC-TiO
2
) were systematically evaluated for exosome isolation from human plasma and thus proteomic analysis. The results demonstrated that the SEC-based tandem methods were superior to the direct SEC method in the purity of exosomes isolated from human plasma. Additionally, the SEC-UC method possessed the highest number of the total identified proteins and the overlapped proteins with the top 100 exosome markers in comparison with the other methods. The SEC-TiO
2
method displayed the biggest capacity for plasma protein deleting. We expect that the research will have more beneficial values in the field of exosome research.
The capacities of four different size exclusion chromatography (SEC)-based methods were evaluated for the purpose of establishing a "gold standard method" for isolation of exosomes from human plasma and thus accurate proteomic analysis.
The multifluid Lyon‐Fedder‐Mobarry (MFLFM) global magnetosphere model is used to study the interactions between solar wind and rapidly rotating, internally driven Jupiter magnetosphere. The MFLFM ...model is the first global simulation of Jupiter magnetosphere that captures the Kelvin‐Helmholtz instability (KHI) in the critically important subsolar region. Observations indicate that Kelvin‐Helmholtz vortices are found predominantly in the dusk sector. Our simulations explain that this distribution is driven by the growth of KHI modes in the prenoon and subsolar region (e.g., >10 local time) that are advected by magnetospheric flows to the dusk sector. The period of density fluctuations at the dusk terminator flank (18 magnetic local time, MLT) is roughly 1.4 h compared with 7.2 h at the dawn flank (6 MLT). Although the simulations are only performed using parameters of the Jupiter's magnetosphere, the results may also have implications for solar wind‐magnetosphere interactions at other corotation‐dominated systems such as Saturn. For instance, the simulated average azimuthal speed of magnetosheath flows exhibit significant dawn‐dusk asymmetry, consistent with recent observations at Saturn. The results are particularly relevant for the ongoing Juno mission and the analysis of dawnside magnetopause boundary crossings for other planetary missions.
Key Points
KHI in the subsolar region is critically important for boundary layer dynamics in Jupiter's magnetosphere
Simulations show that duskward moving KH waves originate at around 10 MLT, and stationary KH waves form on the dawnside around 08‐09 MLT
Duskside density fluctuations associated with KHI exhibit much longer periodicity compared to those on the dawnside
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The aim of this study was to investigate whether microRNA-150-5p was involved in osteosarcoma cell proliferation and invasiveness via modulating vascular endothelial growth factor A (VEGFA) ...expression.
10 pairs of osteosarcoma tissues and para-cancerous tissues were collected from patients with osteosarcoma in our center from February 2012 to July 2018. Relative expression levels of microRNA-150-5p and VEGFA in tissues and cell lines were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Luciferase reporter gene assay was conducted to illustrate the binding interplay between microRNA-150-5p and VEGFA. Furthermore, proliferative and invasive potentials in HOS and MG-63 cells regulated by both microRNA-150-5p and VEGFA were determined using Cell Counting Kit-8 (CCK-8), colony formation assay, and transwell assay, respectively.
MicroRNA-150-5p was remarkably downregulated, while VEGFA was upregulated in osteosarcoma tissues compared with para-cancerous tissues (p<0.05). Similar results were observed in osteosarcoma cells and normal osteoblasts. Overexpression of microRNA-150-5p significantly inhibited the proliferation and invasion of osteosarcoma cells (p<0.05). Luciferase reporter gene assay demonstrated that microRNA-150-5p could target to VEGFA to negatively modulate its expression. In addition, the knockdown of VEGFA remarkably weakened osteosarcoma cell proliferative and invasive capacities (p<0.05).
MicroRNA-150-5p weakens proliferative and invasive potentials in osteosarcoma cells by downregulating VEGFA level. All our findings suggest that microRNA-150-5p/VEGFA axis is a promising target for osteosarcoma treatment.
Abstract
Interactions between a T cell receptor (TCR) and a peptide-major histocompatibility complex (pMHC) ligand are typically mediated by noncovalent bonds. By studying T cells expressing natural ...or engineered TCRs, here we describe covalent TCR-pMHC interactions that involve a cysteine-cysteine disulfide bond between the TCR and the peptide. By introducing cysteines into a known TCR-pMHC combination, we demonstrate that disulfide bond formation does not require structural rearrangement of the TCR or the peptide. We further show these disulfide bonds still form even when the initial affinity of the TCR-pMHC interaction is low. Accordingly, TCR-peptide disulfide bonds facilitate T cell activation by pMHC ligands with a wide spectrum of affinities for the TCR. Physiologically, this mechanism induces strong Zap70-dependent TCR signaling, which triggers T cell deletion or agonist selection in the thymus cortex. Covalent TCR-pMHC interactions may thus underlie a physiological T cell activation mechanism that has applications in basic immunology and potentially in immunotherapy.
ABSTRACT II UMa is a late F-type (F5) contact binary with a close-in tertiary and a distant visual companion. According to the four-color (B V RcIc) light curves' solutions of II UMa, it is a high ...fill-out (f = ) and low-mass ratio (q = 0.172) contact binary system, which indicates that it is at the late evolutionary stage of late-type tidal-locked binary stars. The masses of the primary star and secondary star are calculated to be and . The primary star has evolved from the zero-age main sequence, but it still appeared before the terminal-age main sequence, and the secondary star is even more evolved. Considering the mass ratio ( ) obtained by spectroscopic observations, the mass of the close-in tertiary is estimated to be . The period variations of the binary system are investigated for the first time. According to the observed-calculated (O−C) curve analysis, a continuous period increase at a rate of is determined. The parabolic variation in the O−C curve may be part of a cyclic period of change, or the combined period of change of a parabolic variation and a cyclic one. More instances of minimum light are needed to confirm this. The presence of the tertiary component may play an important role in the formation and evolution of this binary system by drawing angular momentum from the central system during the pre-contact stage.
A color center in c-BN which is isoelectronic to diamond NV⁻ is predicted based on first-principles electronic structure calculations using the Heyd-Scuseria-Ernzerhof hybrid functional. The defect ...consists of a substitutional oxygen and an adjacent boron vacancy (O(N)-V(B)). We find that the O(N)-V(B) center is optically accessible with a zero-phonon line of about 1.6 eV. The O(N)-V(B) center also shares much of the characteristics of the GC-2 center often observed in c-BN. A prominent vibronic coupling peak is predicted to be around 55 meV, which is in excellent agreement with the characteristic phonon frequency (56 meV) observed in the luminescence spectra of the GC-2 center.
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