1,508 research outputs found
Relativistic Brueckner-Hartree-Fock in nuclear matter without the average momentum approximation
Brueckner-Hartree-Fock theory allows to derive the -matrix as an effective
interaction between nucleons in the nuclear medium. It depends on the center of
mass momentum of the two particles and on the two relative momenta
and before and after the scattering process. In the
evaluation of the total energy per particle in nuclear matter usually the angle
averaged center of mass momentum approximation has been used. We derive in
detail the exact expressions of the angular integrations of the momentum
within relativistic Brueckner-Hartree-Fock (RBHF) theory, especially
for the case of asymmetric nuclear matter. In order to assess the reliability
of the conventional average momentum approximation for the binding energy, the
saturation properties of symmetric and asymmetric nuclear matter are
systematically investigated based on the realistic Bonn nucleon-nucleon
potential. It is found that the exact treatment of the center of mass momentum
leads to non-negligible contributions to the higher order physical quantities.
The correlation between the symmetry energy , the slope
parameter , and the curvature of the symmetry energy are
investigated. The results of our RBHF calculations for the bulk parameters
characterizing the equation of state are compared with recent constraints
extracted from giant monopole resonance and isospin diffusion experiments.Comment: 28 pages, 5 figure
Coexistence of ferromagnetism, antiferromagnetism, and superconductivity in magnetically anisotropic (Eu,La)FeAs2
Materials with exceptional magnetism and superconductivity usually conceive
emergent physical phenomena. Here, we investigate the physical properties of
the (Eu,La)FeAs2 system with double magnetic sublattices. The parent EuFeAs2
shows anisotropy-associated magnetic behaviors, such as Eu-related moment
canting and exchange bias. Through La doping, the magnetic anisotropy is
enhanced with ferromagnetism of Eu2+ realized in the overdoped region, and a
special exchange bias of the superposed ferromagnetic/superconducting loop
revealed in Eu0.8La0.2FeAs2. Meanwhile, the Fe-related antiferromagnetism shows
unusual robustness against La doping. Theoretical calculation and 57Fe
M\"ossbauer spectroscopy investigation reveal a doping-tunable dual
itinerant/localized nature of the Fe-related antiferromagnetism. Coexistence of
the Eu-related ferromagnetism, Fe-related robust antiferromagnetism, and
superconductivity is further revealed in Eu0.8La0.2FeAs2, providing a platform
for further exploration of potential applications and emergent physics.
Finally, an electronic phase diagram is established for (Eu,La)FeAs2 with the
whole superconducting dome adjacent to the Fe-related antiferromagnetic phase,
which is of benefit for seeking underlying clues to high-temperature
superconductivity.Comment: 13 pages, 6 figures for the main tex
Differential Gene Expression in Primary Cultured Sensory and Motor Nerve Fibroblasts
Fibroblasts (Fbs) effectively promote Schwann cells (SCs) migration, proliferation, and neurite regeneration. Whether Fbs express different motor and sensory phenotypes that regulate the cell behavior and peripheral nerve function has not been elucidated. The present study utilized the whole rat genome microarray analysis and identified a total of 121 differentially expressed genes between the primary cultured motor and sensory Fbs. The genes with high expression in sensory Fbs were related to proliferation, migration, chemotaxis, motility activation, protein maturation, defense response, immune system, taxis, and regionalization, while those with high expression in motor Fbs were related to neuron differentiation, segmentation, and pattern specification. Thus, the significant difference in the expression of some key genes was found to be associated with cell migration and proliferation, which was further validated by quantitative real-time PCR (qPCR). The cell proliferation or migration analysis revealed a higher rate of cell migration and proliferation of sensory Fbs than motor Fbs. Moreover, the downregulated expression of chemokine (C-X-C motif) ligand 10 (CXCL10) and chemokine (C-X-C motif) ligand 3 (CXCL3) suppressed the proliferation rate of sensory Fbs, while it enhanced that of the motor Fbs. However, the migration rate of both Fbs was suppressed by the downregulated expression of CXCL10 or CXCL3. Furthermore, a higher proportion of motor or sensory SCs migrated toward their respective (motor or sensory) Fbs; however, few motor or sensory SCs co-cultured with the other type of Fbs (sensory or motor, respectively), migrated toward the Fbs. The current findings indicated that Fbs expressed the distinct motor and sensory phenotypes involved in different patterns of gene expression, biological processes, and effects on SCs. Thus, this study would provide insights into the biological differences between motor and sensory Fbs, including the role in peripheral nerve regeneration
Design of broadband metamaterial-based ferromagnetic absorber
In this paper, a metamaterial-based ferromagnetic absorber has been designed at microwave frequencies. The proposed absorber is composed of a periodic array of stacked circular ferromagnetic patches fabricated on the FR4 substrate. With the ferromagnetic property, the single-layer patch array generates a good resonant absorption mode. By stacking multiple ferromagnetic patches, the designed absorber with the absorption above 90% has a wide absorption bandwidth from 10 to 21 GHz. Due to the symmetric structure, the proposed absorber is polarization insensitive. At oblique incident with the incident angle of 45o, the good absorption more than 80% can be achieved in the whole operation band
Interferon regulatory factor-1 together with reactive oxygen species promotes the acceleration of cell cycle progression by up-regulating the cyclin E and CDK2 genes during high glucose-induced proliferation of vascular smooth muscle cells
BACKGROUND: The high glucose-induced proliferation of vascular smooth muscle cells (VSMCs) plays an important role in the development of diabetic vascular diseases. In a previous study, we confirmed that Interferon regulatory factor-1 (Irf-1) is a positive regulator of the high glucose-induced proliferation of VSMCs. However, the mechanisms remain to be determined. METHODS: The levels of cyclin/CDK expression in two cell models involving Irf-1 knockdown and overexpression were quantified to explore the relationship between Irf-1 and its downstream effectors under normal or high glucose conditions. Subsequently, cells were treated with high glucose/NAC, normal glucose/H(2)O(2), high glucose/U0126 or normal glucose/H(2)O(2)/U0126 during an incubation period. Then proliferation, cyclin/CDK expression and cell cycle distribution assays were performed to determine whether ROS/Erk1/2 signaling pathway was involved in the Irf-1-induced regulation of VSMC growth under high glucose conditions. RESULTS: We found that Irf-1 overexpression led to down-regulation of cyclin D1/CDK4 and inhibited cell cycle progression in VSMCs under normal glucose conditions. In high glucose conditions, Irf-1 overexpression led to an up-regulation of cyclin E/CDK2 and an acceleration of cell cycle progression, whereas silencing of Irf-1 suppressed the expression of both proteins and inhibited the cell cycle during the high glucose-induced proliferation of VSMCs. Treatment of VSMCs with antioxidants prevented the Irf-1 overexpression-induced proliferation of VSMCs, the up-regulation of cyclin E/CDK2 and the acceleration of cell cycle progression in high glucose conditions. In contrast, under normal glucose conditions, H(2)O(2) stimulation and Irf-1 overexpression induced cell proliferation, up-regulated cyclin E/CDK2 expression and promoted cell cycle acceleration. In addition, overexpression of Irf-1 promoted the activation of Erk1/2 and when VSMCs overexpressing Irf-1 were treated with U0126, the specific Erk1/2 inhibitor abolished the proliferation of VSMCs, the up-regulation of cyclin E/CDK2 and the acceleration of cell cycle progression under high glucose or normal glucose/H(2)O(2) conditions. CONCLUSIONS: These results demonstrate that the downstream effectors of Irf-1 are cyclin E/CDK2 during the high glucose-induced proliferation of VSMCs, whereas they are cyclin D1/CDK4 in normal glucose conditions. The Irf-1 overexpression-induced proliferation of VSMCs, the up-regulation of cyclin E/CDK2 and the acceleration of cell cycle progression are associated with ROS/Erk1/2 signaling pathway under high glucose conditions
Applications of Direct Injection Soft Chemical Ionisation-Mass Spectrometry for the Detection of Pre-blast Smokeless Powder Organic Additives
Analysis of smokeless powders is of interest from forensics and security perspectives. This article reports the detection of smokeless powder organic additives (in their pre-detonation condition), namely the stabiliser diphenylamine and its derivatives 2-nitrodiphenylamine and 4-nitrodiphenylamine, and the additives (used both as stabilisers and plasticisers) methyl centralite and ethyl centralite, by means of swab sampling followed by thermal desorption and direct injection soft chemical ionisation-mass spectrometry. Investigations on the product ions resulting from the reactions of the reagent ions H3O+ and O2+ with additives as a function of reduced electric field are reported. The method was comprehensively evaluated in terms of linearity, sensitivity and precision. For H3O+, the limits of detection (LoD) are in the range of 41-88 pg of additive, for which the accuracy varied between 1.5 and 3.2%, precision varied between 3.7 and 7.3% and linearity showed R20.9991. For O2+, LoD are in the range of 72 to 1.4 ng, with an accuracy of between 2.8 and 4.9% and a precision between 4.5 and 8.6% and R20.9914. The validated methodology was applied to the analysis of commercial pre-blast gun powders from different manufacturers.(VLID)4826148Accepted versio
The Traitor
The
proteolytic activation of protein kinase CĪ“ (PKCĪ“)
generates a catalytic fragment called PKCĪ“-CF, which induces
cell death. However, the mechanisms underlying PKCĪ“-CF-mediated
cell death are largely unknown. On the basis of an engineering leukemic
cell line with inducible expression of PKCĪ“-CF, here we employ
SILAC-based quantitative phosphoproteomics to systematically and dynamically
investigate the overall phosphorylation events during cell death triggered
by PKCĪ“-CF expression. Totally, 3000 phosphorylation sites were
analyzed. Considering the fact that early responses to PKCĪ“-CF
expression initiate cell death, we sought to identify pathways possibly
related directly with PKCĪ“ by further analyzing the data set
of phosphorylation events that occur in the initiation stage of cell
death. Interacting analysis of this data set indicates that PKCĪ“-CF
triggers complicated networks to initiate cell death, and motif analysis
and biochemistry verification reveal that several kinases in the downstream
of PKCĪ“ conduct these networks. By analysis of the specific
sequence motif of kinase-substrate, we also find 59 candidate substrates
of PKCĪ“ from the up-regulated phosphopeptides, of which 12 were
randomly selected for <i>in vitro</i> kinase assay and 9
were consequently verified as substrates of PKCĪ“. To our greatest
understanding, this study provides the most systematic analysis of
phosphorylation events initiated by the cleaved activated PKCĪ“,
which would vastly extend the profound understanding of PKCĪ“-directed
signal pathways in cell death. The MS data have been deposited to
the ProteomeXchange with identifier PXD000225
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
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