230 research outputs found

    Quantum parametric amplifiation of phonon-mediated magnon-spin interaction

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    The recently developed hybrid magnonics provides new opportunities for advances in both the study of magnetism and the development of quantum information processing. However, engineering coherent quantum state transfer between magnons and specific information carriers, in particular, mechanical oscillators and solid-state spins, remains challenging due to the intrinsically weak interactions and the frequency mismatch between diffrent components. Here, we show how to strongly couple the magnon modes in a nanomagnet to the quantized mechanical motion (phonons) of a micromechanical cantilever in a hybrid tripartite system. The coherent and enhanced magnon-phonon coupling is engineered by introducing the quantum parametric amplifiation of the mechanical motion. With experimentally feasible parameters, we show that the mechanical parametric drive can be adjusted to drive the system into the strong-coupling regime and even the ultrastrong-coupling regime. Furthermore, we show the coherent state transfer between the nanomagnet and a nitrogen-vacancy center in the dispersive-coupling regime, with the magnon-spin interaction mediated by the virtually-excited squeezed phonons. The amplifid mechanical noise can hardly interrupt the coherent dynamics of the system even for low mechanical quality factors, which removes the requirement of applying additional engineered-reservoir techniques. Our work opens up prospects for developing novel quantum transducers, quantum memories and high-precision measurements.Comment: 14 pages, 4 figure

    Compound Bieshe Kangā€™ai inhibits proliferation and induces apoptosis in HCT116 human colorectal cancer cells

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    Purpose: To study the effect of Compound Bieshe Kangā€™ai (CBK) on proliferation and apoptosis in colorectal cancer cells.Methods: HCT116 colorectal cancer cells and FHs 74 Int intestinal cells were treated with CBK, followed by determination of cell proliferation with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Caspase-9 and caspase-3 activities as well as protein expressions of Bcl-2 and BAX, and mRNA levels of caspase-9, caspase-3, Bcl-2 and BAX in HCT116 cells were evaluated, followed by examination of the morphological alterations of HCT116 cells with Hoechst 33342 staining.Results: CBK suppressed proliferation of HCT116 cells in a concentration- and time-dependent pattern, without cytotoxicity to FHs 74 Int cells. CBK also elevated caspase-9 and caspase-3 activities, mitigated protein translation of Bcl-2 and augmented that of BAX. It also enhanced mRNA transcriptions of caspase-9, caspase-3 and BAX, but decreased that of Bcl-2 in HCT116 cells in aĀ  concentrationdependent manner, as well as induced cancer cell shrinkage, nuclear fragmentation and chromatin condensation.Conclusion: The findings highlight CBK as a promising therapeutic agent for colorectal cancers, by retarding proliferation and inducing apoptosis in cancer cells.Keywords: Apoptosis, BAX, Bcl-2, Cancer, Caspase, Compound Bieshe Kangā€™ai, Chromatin condensation, Nuclear fragmentatio

    An HĪ±\alpha Imaging Survey of the Low-surface-brightness Galaxies Selected from the Fall Sky Region of the 40%\% ALFALFA \ion{H}{1} Survey

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    We present the observed HĪ±\alpha flux and derived star formation rates (SFRs) for a fall sample of lowāˆ’-surfaceāˆ’-brightness galaxies (LSBGs). The sample is selected from the fall sky region of the 40%\% ALFALFA {\ion{H}{1}} survey āˆ’- SDSS DR7 photometric data, and all the HĪ±H\alpha images were obtained using the 2.16 m telescope, operated by the National Astronomy Observatories, Chinese Academy of Sciences. A total of 111 LSBGs were observed and HĪ±H\alpha flux was measured in 92 of them. Though almost all the LSBGs in our sample are {\ion{H}{1}}āˆ’-rich, their SFRs derived from the extinction and filterāˆ’-transmissionāˆ’-corrected HĪ±H\alpha flux, are less than 1M_{\sun}yrāˆ’1yr^{-1}. LSBGs and star forming galaxies have similar {\ion{H}{1}} surface densities, but LSBGs have much lower SFRs and SFR surface densities than starāˆ’-forming galaxies. Our results show that LSBGs deviate from the Kennicutt-Schmidt law significantly, which indicate that they have low star formation efficiency. The SFRs of LSBGs are close to average SFRs in Hubble time and support the previous arguments that most of the LSBGs are stable systems and they tend to seldom contain strong interactions or major mergers during their star formation histories

    An HĪ±\alpha Imaging Survey of the Low-surface-brightness Galaxies Selected from the Fall Sky Region of the 40%\% ALFALFA \ion{H}{1} Survey

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    We present the observed HĪ±\alpha flux and derived star formation rates (SFRs) for a fall sample of lowāˆ’-surfaceāˆ’-brightness galaxies (LSBGs). The sample is selected from the fall sky region of the 40%\% ALFALFA {\ion{H}{1}} survey āˆ’- SDSS DR7 photometric data, and all the HĪ±H\alpha images were obtained using the 2.16 m telescope, operated by the National Astronomy Observatories, Chinese Academy of Sciences. A total of 111 LSBGs were observed and HĪ±H\alpha flux was measured in 92 of them. Though almost all the LSBGs in our sample are {\ion{H}{1}}āˆ’-rich, their SFRs derived from the extinction and filterāˆ’-transmissionāˆ’-corrected HĪ±H\alpha flux, are less than 1M_{\sun}yrāˆ’1yr^{-1}. LSBGs and star forming galaxies have similar {\ion{H}{1}} surface densities, but LSBGs have much lower SFRs and SFR surface densities than starāˆ’-forming galaxies. Our results show that LSBGs deviate from the Kennicutt-Schmidt law significantly, which indicate that they have low star formation efficiency. The SFRs of LSBGs are close to average SFRs in Hubble time and support the previous arguments that most of the LSBGs are stable systems and they tend to seldom contain strong interactions or major mergers during their star formation histories

    Gene identification and transcriptome analysis of cadmium stress in tomato

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    Cadmium (Cd) is a highly toxic heavy metal that can severely hinder plant growth and development. Tomato is one of the most important economical crops in the world, and its quality and safety are closely related to human health. Therefore, it is important to elucidate the molecular mechanisms involved in tomato plant responses to Cd stress. In this study, tomato plants were treated with or without 100ā€‰Ī¼M Cd2+ in hydroponic culture for 3ā€‰days. Transcriptional changes in tomato roots and shoots were examined by transcriptome sequencing techniques. A total of 1,123 differentially expressed genes (DEGs) were identified in roots and 159 DEGs were identified in shoots after Cd treatment, including 15 DEGs were upregulated and 24 DEGs were downregulated in both roots and shoots. KEGG enrichment analysis showed that DEGs in the roots and shoots under Cd stress were significantly enriched in the glutathione metabolism pathway, sulfur metabolism pathway, phenylpropanoid biosynthesis, plant-pathogen interaction cutin pathway, suberine and wax biosynthesis pathway, and photosynthesis-antenna proteins pathway. 15 DEGs were further validated by quantitative real-time RT-PCR, including ABC transporter genes, WRKY transcription factors, and NAC transcription factors, among others. This study will provide a theoretical basis for further research on the molecular mechanisms involved in tomato responses to Cd stress, and genetic improvement of Cd tolerance

    Expression of Human Leukocyte Antigen G is associated with Prognosis in Nasopharyngeal Carcinoma

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    Human leukocyte antigen G (HLA-G) has multiple immune regulatory functions including the induction of immune tolerance in malignancies. The roles of HLA-G have not been investigated in nasopharyngeal carcinoma (NPC). This study is aimed to evaluate the role of HLA-G as prognostic factor for NPC patients as well as its role in the immune regulation. Western assays showed high HLA-G expression in NPC cell lines, but low in the immortalized nasopharyngeal epithelial cell line NP69. HLA-G protein was further detected in 79.2% of 552 NPC specimens with immunohistochemistry (IHC), but not in normal nasopharyngeal epithelium tissue. Moreover, high expression of HLA-G predicted poor survival of NPC patients and positively correlated with tumor N classification and recurrence or metastasis. Multivariate analysis indicated that HLA-G was an independent and unfavorable prognostic factor. Furthermore, the presence of CD68+macrophages and IL-10 were also examined, which are two prognostic markers of NPC and important factors for regulating immune surveillance. The correlations of HLA-G with these two immune factors were revealed in NPC tissues. Taken together, our results suggest that HLA-G is an independent biomarker for NPC prognosis, and HLA-G might contribute to NPC progression, which might jointly regulate immune surveillance in NPC together with macrophages and IL-10

    The LAMOST Complete Spectroscopic Survey of Pointing Area (LaCoSSPAr) in the Southern Galactic Cap I. The Spectroscopic Redshift Catalog

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    We present a spectroscopic redshift catalog from the LAMOST Complete Spectroscopic Survey of Pointing Area (LaCoSSPAr) in the Southern Galactic Cap (SGC), which is designed to observe all sources (Galactic and extra-galactic) by using repeating observations with a limiting magnitude of r=18.1Ā magr=18.1~mag in two 20Ā deg220~deg^2 fields. The project is mainly focusing on the completeness of LAMOST ExtraGAlactic Surveys (LEGAS) in the SGC, the deficiencies of source selection methods and the basic performance parameters of LAMOST telescope. In both fields, more than 95% of galaxies have been observed. A post-processing has been applied to LAMOST 1D spectrum to remove the majority of remaining sky background residuals. More than 10,000 spectra have been visually inspected to measure the redshift by using combinations of different emission/absorption features with uncertainty of Ļƒz/(1+z)<0.001\sigma_{z}/(1+z)<0.001. In total, there are 1528 redshifts (623 absorption and 905 emission line galaxies) in Field A and 1570 redshifts (569 absorption and 1001 emission line galaxies) in Field B have been measured. The results show that it is possible to derive redshift from low SNR galaxies with our post-processing and visual inspection. Our analysis also indicates that up to 1/4 of the input targets for a typical extra-galactic spectroscopic survey might be unreliable. The multi-wavelength data analysis shows that the majority of mid-infrared-detected absorption (91.3%) and emission line galaxies (93.3%) can be well separated by an empirical criterion of W2āˆ’W3=2.4W2-W3=2.4. Meanwhile, a fainter sequence paralleled to the main population of galaxies has been witnessed both in MrM_r/W2āˆ’W3W2-W3 and Māˆ—M_*/W2āˆ’W3W2-W3 diagrams, which could be the population of luminous dwarf galaxies but contaminated by the edge-on/highly inclined galaxies (āˆ¼30%\sim30\%).Comment: 19 pages, 14 figures, 2 MRT, accepted by ApJ

    Increased origin activity in transformed versus normal cells: identification of novel protein players involved in DNA replication and cellular transformation

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    Using libraries of replication origins generated previously, we identified three clones that supported the autonomous replication of their respective plasmids in transformed, but not in normal cells. Assessment of their in vivo replication activity by in situ chromosomal DNA replication assays revealed that the chromosomal loci corresponding to these clones coincided with chromosomal replication origins in all cell lines, which were more active by 2ā€“3-fold in the transformed by comparison to the normal cells. Evaluation of pre-replication complex (pre-RC) protein abundance at these origins in transformed and normal cells by chromatin immunoprecipitation assays, using anti-ORC2, -cdc6 and -cdt1 antibodies, showed that they were bound by these pre-RC proteins in all cell lines, but a 2ā€“3-fold higher abundance was observed in the transformed by comparison to the normal cells. Electrophoretic mobility shift assays (EMSAs) performed on the most efficiently replicating clone, using nuclear extracts from the transformed and normal cells, revealed the presence of a DNA replication complex in transformed cells, which was barely detectable in normal cells. Subsequent supershift EMSAs suggested the presence of transformation-specific complexes. Mass spectrometric analysis of these complexes revealed potential new protein players involved in DNA replication that appear to correlate with cellular transformation
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