Observation of e+e- → γX(3872) at BESIII Achasov, M N; Albayrak, O; Ambrose, D J ...
Physical review letters,
2014-Mar-07, Letnik:
112, Številka:
9
Journal Article
Recenzirano
Odprti dostop
With data samples collected with the BESIII detector operating at the BEPCII storage ring at center-of-mass energies from 4.009 to 4.420 GeV, the process e+e-→ γX(3872) is observed for the first time ...with a statistical significance of 6.3σ. The measured mass of the X(3872) is (3871.9 ± 0.7s tat ± 0.2 syst) MeV/c(2), in agreement with previous measurements. Measurements of the product of the cross section σe+e- → γX(3872) and the branching fraction BX(3872)→π+π-J/ψ at center-of-mass energies 4.009, 4.229, 4.260, and 4.360 GeV are reported. Our measurements are consistent with expectations for the radiative transition process Y(4260) → γX(3872).
The occurrence and progression of hepatocellular carcinoma (HCC) is a multi-step complex process and the exact molecular mechanisms remain to be elucidated. LncRNA NEAT1 is involved in tumorigenesis ...and progression. However, the role of LncRNA NEAT1 in HCC remains unclear.
The tumor tissues and adjacent tissues of HCC patients were collected and LncRNA NEAT1 expression was detected by Real time PCR. The hepatoma cell line HepG2 was cultured and transfected with lnc RNA NEAT1 siRNA or lnc RNA NEAT1 plasmid followed by analysis of LncRNA NEAT1 expression, cell proliferation by MTT assay, as well as Caspase 3 activity. In addition, cell apoptosis and cell cycle were assessed by flow cytometry and cell invasion was measured by transwell chambers. The expression of EGFR, Bax and Bcl-2 was detected by Western blot.
LncRNA NEAT1 expression was significantly increased in HCC tissues compared with adjacent tissues (p < 0.05). Compared with the siRNA group, transfection of lncRNA NEAT1 siRNA into HepG2 cells significantly inhibited cell proliferation, increased Caspase 3 activity and apoptosis, reduced cell invasion, as well as arrested cell cycle (p < 0.05). Meanwhile, lncRNA NEAT1 siRNA also significantly decreased Bcl-2 and EGFR expression and increased Bax expression (p < 0.05). Transfection of lncRNA NEAT1 plasmid in hepatoma cells HepG2 reversed the above changes, compared with vector group, the differences were statistically significant (p < 0.05).
LncRNA NEAT1 expression is increased in liver cancer tissues. Down-regulation of LncRNA NEAT1 can inhibit EGFR expression and promote hepatoma cell apoptosis, inhibit cell cycle, thus inhibiting tumor proliferation and invasion.
Visibility impairment has become an important environmental issue receiving great attention from both the scientific community and the public. Long-term meteorological data from Baoji, China, were ...collected to investigate the trend in visibility change from 1980 to 2012. The 33-year average visual range is 12.0km. The best 20% of the visibility observations in a calendar year shows a general decreasing trend from 1994 onwards, while the worst 20% exhibits a slight increasing trend from 1997 onwards. These results suggest the progressive degradation of air quality in Baoji in recent years. Intensive PM2.5 measurements were conducted from March 2012 to February 2013 to determine the causes of visibility impairment. An analysis based on IMPROVE equation reveals that PM2.5 organic matter (OM) contributes to 34.2% of the light extinction coefficient (bext) on an annual basis, followed by (NH4)2SO4 (30.0%), NH4NO3 (20.1%), elemental carbon (9.2%) and soil dust (6.5%). The largest contributor to bext for the Worst 20% group is (NH4)2SO4, and the contribution of NH4NO3 for the Worst 20% group increases by a factor of ~3 compared with the Best 20% group. Source apportionment using a positive matrix factorization receptor model indicates that secondary sulfate is the main source of PM2.5 (23.0%), followed by fugitive dust (20.5%), coal combustion (19.9%), secondary nitrate (15.5%), biomass burning (14.3%) and motor vehicle emissions (6.8%). These quantitative results could be useful for policy makers to take effective measures to control the haze pollution in Baoji. Further, the results also are likely to be relevant for other mid-sized cities in China.
•The 33-year average visual range is 12.0km.•(NH4)2SO4 is the largest contributor to bext for the worst 20% group.•Secondary sulfate, fugitive dust and coal combustion are the main sources of PM2.5.
Summary
Variations in ear size can be observed in livestock such as sheep; however, the genetic basis of variable ear size in sheep is still poorly understood. To investigate causative genes ...associated with ear size in sheep, a genome‐wide association study was performed in 115 adult Duolang sheep with different‐sized floppy ears using the Ovine Infinium HD BeadChip. We found 38 significant SNPs at the genome‐wide or chromosome‐wise 5% significance level after Bonferroni correction. The most significant association (P = 1.61 × 10−6) was found at SNP rs402740419, located in the DCC gene, which plays a critical role in ear development. Also, we observed two additional significant SNPs, rs407891215 in PTPRD and rs407769095 in SOX5, both of which are functionally associated with ear developmental processes. Our results are useful for future sheep breeding and provide insights into the genetic basis of ear size development in sheep and other livestock.
Nanocomposites can provide exciting physical, chemical, and mechanical properties for numerous applications. The solidification processing method has great potential for economical fabrication of ...bulk nanocomposites, especially for those with crystalline materials as the matrix, such as metal matrix nanocomposites (MMNCs). However, it is extremely difficult to effectively capture nanoparticles (less than 100 nm) into the solidification fronts during solidification. It is thus very important to initiate a theoretical study to examine the physics that governs the interactions between nanoparticles and the solidification front, and to provide enabling pathways for effective nanoparticle capture during solidification. The aim of this paper is to establish a theoretical framework for the fundamental understanding of nanoparticle capture during solidification of metal melt in order to obtain bulk MMNCs. A thermodynamically favorable condition is set as the starting point for further theoretical analysis of the three-party model system, namely a nanoparticle-metal-melt-solidification front. Three key interaction potentials, the interfacial energy at short range (0.2-0.4 nm), the van der Waals potential (especially at a longer range beyond 0.4 nm and up to ∼10 nm) and the Brownian potential, were studied. Three possible pathways for nanoparticle capture were thus devised: viscous capture, Brownian capture and spontaneous capture. Spontaneous capture is proposed as the most favorable for nanoparticle capture during solidification of metal melt. The theoretical model of nanoparticle capture from this study will serve as a powerful tool for future experimental studies to realize exciting functionalities offered by bulk MMNCs.
Cementum, a specialized bony layer covering an entire molar root surface, anchors teeth into alveolar bone. Gli1, a key transcriptional activator in Hedgehog signaling, has been identified as a ...mesenchymal progenitor cell marker in various tissues, including the periodontal ligament (PDL). To address the mechanisms by which Gli1+ progenitor cells contribute to cementogenesis, we used the Gli1lacZ/+ knock-in line to mark Gli1+ progenitors and the Gli1CreERT2/+; R26RtdTomato/+ line (named Gli1Lin) to trace Gli1 progeny cells during cementogenesis. Our data unexpectedly displayed a biphasic feature of Gli1+ PDL progenitor cells and cementum growth: a negative relationship between Gli1+ progenitor cell number and cementogenesis but a positive correlation between Gli1-derived acellular and cellular cementoblast cell number and cementum growth. DTA-ablation of Gli1Lin cells led to a cementum hypoplasia, including a significant reduction of both acellular and cellular cementoblast cells. Gain-of-function studies (by constitutive stabilization of β-catenin in Gli1Lin cells) revealed a cementum hyperplasia. A loss of function (by conditional deletion of β-catenin in Gli1+ cells) resulted in a reduction of postnatal cementum growth. Together, our studies support a vital role of Gli1+ progenitor cells in contribution to both types of cementum, in which canonical Wnt/β-catenin signaling positively regulates the differentiation of Gli1+ progenitors to cementoblasts during cementogenesis.
Ustilaginoidea virens (Uv), the causative agent of rice false smut disease, infects developing rice spikelets at the booting stage, and transforms individual grains of the panicle into smut balls. ...Epidemics of the disease occur when the rice booting and heading stages coincide with rainy days. Using a green fluorescent protein (GFP)‐labelled Uv isolate that can form false smut balls on rice panicles, it was found that under high humidity and free water conditions the Uv isolate could colonize leaves of plants belonging to various families including the Poaceae (Oryza sativa, Echinochloa crusgalli, Digitaria sanguinalis and Leptochloa chinensis), the Brassicaceae (Arabidopsis thaliana) and the Solanaceae (Nicotiana benthamiana) without symptoms. Over several days, some conidia could germinate on the leaves of these plants and in water on the surface of Parafilm and cellophane, form hyphae and differentiate conidiophores to generate a large number of secondary conidia, while other conidia were able to directly produce secondary conidia. Conversely, in the absence of water some conidia could either bud to form new conidia or were converted into chlamydospores. These data indicate that Uv is one of a few fungal pathogens reported to have epiphytic characteristics. The rapid generation of a large number of spores on biotic and abiotic surfaces greatly increases the inoculum that can infect rice spikelets, resulting in the occurrence of rice false smut disease epidemics. These findings are important in the development of disease control strategies.
Knowledge of the rigidity dependence of the boron to carbon flux ratio (B/C) is important in understanding the propagation of cosmic rays. The precise measurement of the B/C ratio from 1.9 GV to 2.6 ...TV, based on 2.3 million boron and 8.3 million carbon nuclei collected by AMS during the first 5 years of operation, is presented. The detailed variation with rigidity of the B/C spectral index is reported for the first time. The B/C ratio does not show any significant structures in contrast to many cosmic ray models that require such structures at high rigidities. Remarkably, above 65 GV, the B/C ratio is well described by a single power law R^{Δ} with index Δ=-0.333±0.014(fit)±0.005(syst), in good agreement with the Kolmogorov theory of turbulence which predicts Δ=-1/3 asymptotically.
We theoretically demonstrate that the two-dimensional porous C
2
N sheet exhibits an extremely high selectivity and large permeance in favour of H
2
among other atmospheric gases. This experimentally ...available porous C
2
N is superior to traditional membranes, such as polymers and silica, and could have great potential for hydrogen separation.
The two-dimensional porous C
2
N sheet exhibits an extremely high selectivity and large permeance in favour of H
2
among other atmospheric gases.
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