High-energy cosmic-ray electrons and positrons (CREs), which lose energy quickly during their propagation, provide a probe of Galactic high-energy processes and may enable the observation of ...phenomena such as dark-matter particle annihilation or decay. The CRE spectrum has been measured directly up to approximately 2 teraelectronvolts in previous balloon- or space-borne experiments, and indirectly up to approximately 5 teraelectronvolts using ground-based Cherenkov γ-ray telescope arrays. Evidence for a spectral break in the teraelectronvolt energy range has been provided by indirect measurements, although the results were qualified by sizeable systematic uncertainties. Here we report a direct measurement of CREs in the energy range 25 gigaelectronvolts to 4.6 teraelectronvolts by the Dark Matter Particle Explorer (DAMPE) with unprecedentedly high energy resolution and low background. The largest part of the spectrum can be well fitted by a 'smoothly broken power-law' model rather than a single power-law model. The direct detection of a spectral break at about 0.9 teraelectronvolts confirms the evidence found by previous indirect measurements, clarifies the behaviour of the CRE spectrum at energies above 1 teraelectronvolt and sheds light on the physical origin of the sub-teraelectronvolt CREs.
Abstract Background Exosomes are nanometer-sized vesicles that are released by normal and neoplastic cells. Previous studies have focused on the interaction between tumour-derived exosomes and the ...immune system, as a consequence of immune suppression or enhancement. However, the effects of tumour-derived exosomes on tumour cells themselves have not been well studied. Aims To investigate the effects of gastric cancer exosomes on tumour cell proliferation and the possible mechanisms. Methods By serial centrifugation and sucrose gradient ultracentrifugation, we isolated and purified the exosomes from gastric cancer SGC7901 cells, then viewed them by electron microscopy. Cell proliferation was measured by 3-(4,5-dimethylthiazol)-2,5-diphenyltetrazolium bromide assay. Protein expression was assayed by Western blotting. Results SGC7901-cell-derived exosomes promoted the proliferation of SGC7901 and BGC823 cells. The increase in proliferation induced by exosomes was accompanied by activation of Akt and extracellular-regulated protein kinase, and phosphoinositide 3-kinase or extracellular-regulated protein kinase inhibitor partially reversed the proliferative effect of exosomes. Moreover, the exosome-induced increase in activity of Akt and extracellular-regulated protein kinase coincided with decreased expression of the Casitas B-lineage lymphoma family of ubiquitin ligases. Conclusion Gastric cancer exosomes promoted tumour cell proliferation, at least in part, by activation of PI3K/Akt and mitogen-activated protein kinase/extracellular-regulated protein kinase pathways. The decreased expression of Casitas B-lineage lymphoma proteins might have contributed to the activation of Akt and extracellular-regulated protein kinase.
The measurement of the energy spectrum of cosmic ray helium nuclei from 70 GeV to 80 TeV using 4.5 years of data recorded by the Dark Matter Particle Explorer (DAMPE) is reported in this work. A ...hardening of the spectrum is observed at an energy of about 1.3 TeV, similar to previous observations. In addition, a spectral softening at about 34 TeV is revealed for the first time with large statistics and well controlled systematic uncertainties, with an overall significance of 4.3σ. The DAMPE spectral measurements of both cosmic protons and helium nuclei suggest a particle charge dependent softening energy, although with current uncertainties a dependence on the number of nucleons cannot be ruled out.
•We prepared MoSe2 hollow microspheres by template-free hydrothermal process.•The MoSe2 hollow microspheres consist of nanosheets with diameters of ~1.5 μm.•The MoSe2 electrode achieves excellent Na+ ...storage performance as an anode for NIBs.
Molybdenum selenide has attracted considerable attention for sodium-ion batteries (SIBs) due to its excellent reactivity and large capacity compared to other transition metal dichalcogenides (TMDs). Herein, a facile template-free hydrothermal process is conducted to synthesize hierarchical MoSe2 hollow microspheres with the diameters of ~1.5 μm. The as-prepared MoSe2 hollow microspheres consist of cross-linked nanosheets. As an anode of SIBs, the hierarchical MoSe2 hollow microspheres exhibit a high initial discharge capacity of 710.2 mAh g−1. When the current density is as high as 1000 mA g−1, the specific capacity can still maintain at 290 mAh g−1. The excellent cycling performance and rate capability are due to the hollow microspherical architecture, which shortens the diffusion length of Na+, promotes the penetration of electrolyte into active materials and accommodates the volume stress. It is a successful case to obtain hollow architectures to shed some lights on the high-performance SIBs.
The precise measurement of the spectrum of protons, the most abundant component of the cosmic radiation, is necessary to understand the source and acceleration of cosmic rays in the Milky Way. This ...work reports the measurement of the cosmic ray proton fluxes with kinetic energies from 40 GeV to 100 TeV, with 2
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years of data recorded by the DArk Matter Particle Explorer (DAMPE). This is the first time that an experiment directly measures the cosmic ray protons up to ~100 TeV with high statistics. The measured spectrum confirms the spectral hardening at ~300 GeV found by previous experiments and reveals a softening at ~13.6 TeV, with the spectral index changing from ~2.60 to ~2.85. Our result suggests the existence of a new spectral feature of cosmic rays at energies lower than the so-called knee and sheds new light on the origin of Galactic cosmic rays.
The formation and ecological roles of sterile flowers in flowering plants are interesting issues in floral biology and evolution. Here, we investigated the morphological and anatomical ...characteristics of both fertile and sterile flowers of Viburnum macrocephalum f. keteleeri, a self‐incompatible and insect‐pollinated shrub, during different developmental stages of flowers. In addition, pollinator visitation rates and fruit set were determined in intact inflorescences and those with sterile flowers removed. The results indicate that sterile and fertile flowers were developmentally similar during early developmental stages, and that development of the flower types diverged about 15 days before flowering. In addition, pollinator visitation rates, number of pollen grains on stigmas and fruit set were significantly higher in inflorescences with sterile flowers than those without sterile flowers. The results suggest that sterile flowers of this species evolved from fertile flowers under long‐term selective pressure, and play a crucial role in enhancing reproductive success through effectively attracting pollinators to the plant and thus enhancing fruit set.
The ultrasound-guided interscalene block (ISB) has been considered a standard technique in managing pain after shoulder surgery. However, this method was associated with the incidence of ...hemi-diaphragmatic paresis. In contrast to ISB, supraclavicular block (SCB) was suggested to provide effective anaesthesia for shoulder surgery with a low rate of side-effects. Thus, we performed a meta-analysis of randomised controlled trials (RCTs) to compare SCB with ISB for evaluating the efficacy and safety.
The literature was searched from PubMed, Wiley Online Library, EMBASE, and the Cochrane Library by two reviewers up to April 2017. All available RCTs written in English that met the criteria were included. Two authors pulled data from relevant articles and assessed the quality with the Cochrane Handbook. Review Manager 5.3 software was used to analyse the data.
Five RCTs and one prospective clinical study met the eligibility criteria and were included in the meta-analysis. We considered that there were no statistically significant differences between supraclavicular and interscalene groups in procedural time (P = 0.81), rescue analgesia (P = 0.53), and dyspnoea (P = 0.6). The incidence of hoarseness and Horner syndrome was statistically lower in the SCB group than in the ISB group (P = 0.0002 and P < 0.00001, respectively).
The meta-analysis showed that ultrasound-guided SCB could become a feasible alternative technique to the ISB in shoulder surgery.
•The ultrasound-guided interscalene block and Supraclavicular block were both used in managing pain for shoulder surgery.•Supraclavicular block could provide e similar analgesic efficacy compared with interscalene block.•Ultrasound-guided supraclavicular block was associated with a low incidence of hoarseness and Horner syndrome.
Several studies have shown a correlation between glargine use and cancer risk. However, the role of glargine in carcinogenesis, especially in colorectal cancer (CRC), is still inconclusive. The aim ...of this study was to investigate the influence of glargine on proliferation of CRC cells and its possible mechanism. Effect of glargine on the cell proliferation was tested in HCT-116 and SW480 cells by MTT assay, and apoptosis was measured by flow cytometry. The expression of microRNA-95 (miR-95) and sorting nexin 1 (SNX1) protein was also determined by real-time PCR and Western blotting, respectively. The results showed that high dose glargine (from 150 to 300 nM) promoted proliferation and inhibit2ed apoptosis of CRC cells compared with untreated cells. Moreover, glargine could upregulate miR-95 and downregulate SNX1 protein expression in CRC cells. These data show that glargine may indeed trigger cellular proliferation in CRC, probably by regulating miR-95.
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