230 research outputs found
Quantum parametric amplifiation of phonon-mediated magnon-spin interaction
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
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An HĪ± Imaging Survey of All (Ultra)luminous Infrared Galaxies at Decl. ā„ -30 in the GOALS Sample
This paper presents the result of HĪ± imaging for luminous and ultraluminous infrared galaxies. It is a complete subsample of the Great Observatories All-sky LIRG Survey (GOALS) with decl. ā„ -30 , and consists of 148 galaxies with log(L IR/L ) ā„ 11.0. All the HĪ± images were carried out using the 2.16 m telescope at the Xinglong Station of the National Astronomy Observatories, Chinese Academy of Sciences (NAOC), during the year from 2006 to 2009. We obtained the pure HĪ± luminosity for each galaxy and corrected the luminosity for [N ii] emission, filter transmission, and extinction. We also classified these galaxies based on their morphology and interaction. We found that the distribution of star-forming regions in these galaxies is related to this classification. As the merging process advanced, these galaxies tended to have a more compact distribution of star-forming regions, higher L IR, and warmer IR-color (f 60/f 100). These results imply that the degree of dynamical disturbance plays an important role in determining the distribution of a star-forming region
Compound Bieshe Kangāai inhibits proliferation and induces apoptosis in HCT116 human colorectal cancer cells
Purpose: To study the effect of Compound Bieshe Kangāai (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 Kangāai, Chromatin condensation, Nuclear fragmentatio
An H Imaging Survey of the Low-surface-brightness Galaxies Selected from the Fall Sky Region of the 40 ALFALFA \ion{H}{1} Survey
We present the observed H flux and derived star formation rates
(SFRs) for a fall sample of lowsurfacebrightness galaxies (LSBGs). The
sample is selected from the fall sky region of the 40 ALFALFA {\ion{H}{1}}
survey SDSS DR7 photometric data, and all the 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 flux was measured in 92 of them. Though almost all the LSBGs in
our sample are {\ion{H}{1}}rich, their SFRs derived from the extinction and
filtertransmissioncorrected flux, are less than
1M_{\sun}.
LSBGs and star forming galaxies have similar {\ion{H}{1}} surface densities,
but LSBGs have much lower SFRs and SFR surface densities than starforming
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 H Imaging Survey of the Low-surface-brightness Galaxies Selected from the Fall Sky Region of the 40 ALFALFA \ion{H}{1} Survey
We present the observed H flux and derived star formation rates
(SFRs) for a fall sample of lowsurfacebrightness galaxies (LSBGs). The
sample is selected from the fall sky region of the 40 ALFALFA {\ion{H}{1}}
survey SDSS DR7 photometric data, and all the 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 flux was measured in 92 of them. Though almost all the LSBGs in
our sample are {\ion{H}{1}}rich, their SFRs derived from the extinction and
filtertransmissioncorrected flux, are less than
1M_{\sun}.
LSBGs and star forming galaxies have similar {\ion{H}{1}} surface densities,
but LSBGs have much lower SFRs and SFR surface densities than starforming
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
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 100āĪ¼M Cd2+ in hydroponic culture for 3ādays. 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
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
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 in
two 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 . 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 . Meanwhile, a fainter sequence paralleled to the main population
of galaxies has been witnessed both in / and /
diagrams, which could be the population of luminous dwarf galaxies but
contaminated by the edge-on/highly inclined galaxies ().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
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 2ā3-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 2ā3-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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