275 research outputs found
Weak antilocalization and electron-electron interaction in coupled multiple-channel transport in a BiSe thin film
Electron transport properties of a topological insulator BiSe thin
film are studied in Hall-bar geometry. The film with a thickness of 10 nm is
grown by van der Waals epitaxy on fluorophlogopite mica and Hall-bar devices
are fabricated from the as-grown film directly on the mica substrate. Weak
antilocalization and electron-electron interaction effects are observed and
analyzed at low temperatures. The phase-coherence length extracted from the
measured weak antilocalization characteristics shows a strong power-law
increase with decreasing temperature and the transport in the film is shown to
occur via coupled multiple (topological surface and bulk states) channels. The
conductivity of the film shows a logarithmically decrease with decreasing
temperature and thus the electron-electron interaction plays a dominant role in
quantum corrections to the conductivity of the film at low temperatures.Comment: 12 pages, 5 figure
Continuous variable entanglement enhancement and manipulation by a sub-threshold type-II optical parametric amplifier
We experimentally demonstrate that the quantum entanglement between amplitude
and phase quadratures of optical modes produced from a non-degenerate optical
parametric amplifier (NOPA) can be enhanced and manipulated phase-sensitively
by means of another NOPA. When both NOPAs operate at de-amplification, the
entanglement degree is increased at the cavity resonance of the second NOPA.
When the first NOPA operates at de-amplification and the second one at
amplification, the spectral features of the correlation variances are
significantly changed. The experimental results are in good agreement with the
theoretical expectation
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Dual blockage of STAT3 and ERK1/2 eliminates radioresistant GBM cells.
Radiotherapy (RT) is the major modality for control of glioblastoma multiforme (GBM), the most aggressive brain tumor in adults with poor prognosis and low patient survival rate. To improve the RT efficacy on GBM, the mechanism causing tumor adaptive radioresistance which leads to the failure of tumor control and lethal progression needs to be further elucidated. Here, we conducted a comparative analysis of RT-treated recurrent tumors versus primary counterparts in GBM patients, RT-treated orthotopic GBM tumors xenografts versus untreated tumors and radioresistant GBM cells versus wild type cells. The results reveal that activation of STAT3, a well-defined redox-sensitive transcriptional factor, is causally linked with GBM adaptive radioresistance. Database analysis also agrees with the worse prognosis in GBM patients due to the STAT3 expression-associated low RT responsiveness. However, although the radioresistant GBM cells can be resensitized by inhibition of STAT3, a fraction of radioresistant cells can still survive the RT combined with STAT3 inhibition or CRISPR/Cas9-mediated STAT3 knockout. A complementally enhanced activation of ERK1/2 by STAT3 inhibition is identified responsible for the survival of the remaining resistant tumor cells. Dual inhibition of ERK1/2 and STAT3 remarkably eliminates resistant GBM cells and inhibits tumor regrowth. These findings demonstrate a previously unknown feature ofSTAT3-mediated ERK1/2 regulation and an effective combination of two targets in resensitizing GBM to RT
Strong spin-orbit interaction and magnetotransport in semiconductor BiOSe nanoplates
Semiconductor BiOSe nanolayers of high crystal quality have been
realized via epitaxial growth. These two-dimensional (2D) materials possess
excellent electron transport properties with potential application in
nanoelectronics. It is also strongly expected that the 2D BiOSe
nanolayers could be of an excellent material platform for developing spintronic
and topological quantum devices, if the presence of strong spin-orbit
interaction in the 2D materials can be experimentally demonstrated. Here, we
report on experimental determination of the strength of spin-orbit interaction
in BiOSe nanoplates through magnetotransport measurements. The
nanoplates are epitaxially grown by chemical vapor deposition and the
magnetotransport measurements are performed at low temperatures. The measured
magnetoconductance exhibits a crossover behavior from weak antilocalization to
weak localization at low magnetic fields with increasing temperature or
decreasing back gate voltage. We have analyzed this transition behavior of the
magnetoconductance based on an interference theory which describes the quantum
correction to the magnetoconductance of a 2D system in the presence of
spin-orbit interaction. Dephasing length and spin relaxation length are
extracted from the magnetoconductance measurements. Comparing to other
semiconductor nanostructures, the extracted relatively short spin relaxation
length of ~150 nm indicates the existence of strong spin-orbit interaction in
BiOSe nanolayers.Comment: 14 pages, 4 figures, and 5 pages of Supplementary Material
Single-Molecule Real-Time Transcript Sequencing Identified Flowering Regulatory Genes in Crocus Sativus
Background: Saffron crocus (Crocus sativus) is a valuable spice with medicinal uses in gynaecopathia and nervous system diseases. Identify flowering regulatory genes plays a vital role in increasing flower numbers, thereby resulting in high saffron yield.
Results: Two full length transcriptome gene sets of flowering and non-flowering saffron crocus were established separately using the single-molecule real-time (SMRT) sequencing method. A total of sixteen SMRT cells generated 22.85 GB data and 75,351 full-length saffron crocus unigenes on the PacBio RS II panel and further obtained 79,028 SSRs, 72,603 lncRNAs and 25,400 alternative splicing (AS) events. Using an Illumina RNA-seq platform, an additional fifteen corms with different flower numbers were sequenced. Many differential expression unigenes (DEGs) were screened separately between flowering and matched non-flowering top buds with cold treatment (1677), flowering top buds of 20 g corms and non-flowering top buds of 6 g corms (1086), and flowering and matched nonflowering lateral buds (267). A total of 62 putative flower-related genes that played important roles in vernalization (VRNs), gibberellins (G3OX, G2OX), photoperiod (PHYB, TEM1, PIF4), autonomous (FCA) and age (SPLs) pathways were identified and a schematic representation of the flowering gene regulatory network in saffron crocus was reported for the first time. After validation by real-time qPCR in 30 samples, two novel genes, PB.20221.2 (p = 0.004, r = 0.52) and PB.38952.1 (p = 0.023, r = 0.41), showed significantly higher expression levels in flowering plants. Tissue distribution showed specifically high expression in flower organs and time course expression analysis suggested that the transcripts increasingly accumulated during the flower development period.
Conclusions: Full-length transcriptomes of flowering and non-flowering saffron crocus were obtained using a combined NGS short-read and SMRT long-read sequencing approach. This report is the first to describe the flowering gene regulatory network of saffron crocus and establishes a reference full-length transcriptome for future studies on saffron crocus and other Iridaceae plants
Overexpression of IGF2 affects mouse weight and glycolipid metabolism and IGF2 is positively related to macrosomia
ObjectiveTo investigate the effects of insulin-like growth factor 2 (IGF2) on growth and glycolipid metabolism, as well as the underlying mechanism.MethodsA mouse model of IGF2 overexpression was constructed to measure weight gain before adulthood, to obtain the values of adult glycolipid metabolism indicators in the peripheral blood and to detect the expression of genes in the IGF2 signaling pathway in different mouse tissues. The present study also explored the independent association between the IGF2 gene and macrosomia by detecting and comparing the expression levels of IGF2 mRNA/H19 RNA in maternal peripheral blood and fetal cord blood of 26 human pregnancies.ResultsIn the mouse model, weights of the IGF2-overexpressing mice were significantly higher than those of the control mice at the age of 5-10 weeks. The glucose concentration, total cholesterol and high-density lipoprotein cholesterol (HDL-C) levels of IGF2-overexpressing mice were significantly lower than those of wild-type (WT) mice. Compared with the WT mice, the expression of H19 was significantly decreased in the pancreas and IGF1R was significantly decreased in the muscle of mice with IGF2 overexpression. The expression levels of STAT3 and AKT2 showed significant decrease in liver, muscle and increase in muscle of IGF2-overexpressing mice, respectively. GLUT2 expression showed significant increase in liver, kidney, muscle and decrease in pancreas of mice with IGF2 overexpression. This study also found that in normal mothers with the similar clinical characteristics, IGF2 expression in the maternal peripheral blood and fetal cord blood is an independent factor influencing macrosomia. ConclusionIGF2 expression was independently correlated with the occurrence of macrosomia, and overexpression of IGF2 significantly increased the weights of mice at the age of 5-10 weeks and significantly affected the values of adult glycolipid metabolism indicators, which might be the result of changes in the IGF2-IGF1R-STAT3/AKT2-GLUT2/GLUT4 pathway. These findings might suggest that IGF2 plays an important role in growth and glycolipid metabolism during both pregnancy and postnatal development
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Rab25-Mediated EGFR Recycling Causes Tumor Acquired Radioresistance.
Tumor acquired radioresistance remains as the major limit in cancer radiotherapy (RT). Rab25, a receptor recycling protein, has been reported to be enhanced in tumors with aggressive phenotype and chemotherapy resistance. In this study, elevated Rab25 expression was identified in an array of radioresistant human cancer cell lines, in vivo radioresistant xenograft tumors. Clinical investigation confirmed that Rab25 expression was also associated with a worse prognosis in patients with lung adenocarcinoma (LUAD) and nasopharyngeal carcinoma (NPC). Enhanced activities of EGFR were observed in both NPC and LUAD radioresistant cells. Rab25 interacts with EGFR to enhance EGFR recycling to cell surface and to decrease degradation in cytoplasm. Inhibition of Rab25 showed synergized radiosensitivity with reduced aggressive phenotype. This study provides the clinical and experimental evidence that Rab25 is a potential therapeutic target to alleviate the hyperactive EGFR signaling and to prevent RT-acquired tumor resistance in patients with LUAD and NPC
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