3,867 research outputs found
Novel Non-equilibrium Phase Transition Caused by Non-linear Hadronic-quark Phase Structure
We consider how the occurrence of first-order phase transitions in
non-constant pressure differs from those at constant pressure. The former has
shown the non-linear phase structure of mixed matter, which implies a particle
number dependence of the binding energies of the two species. If the mixed
matter is mixed hadron-quark phase, nucleon outgoing from hadronic phase and
ingoing to quark phase probably reduces the system to a non-equilibrium state,
in other words, there exists the imbalance of the two phases when deconfinement
takes place. This novel non-equilibrium process is very analogous to the
nuclear reactions that nuclei emit neutrons and absorb them under appropriate
conditions. We present self-consistent thermodynamics in description for the
processes and identify the microphysics responsible for the processes. The
microphysics is an inevitable consequence of non-linear phase structure instead
of the effect of an additional dissipation force. When applying our findings to
the neutron star containing mixed hadron-quark matter, it is found that the
newly discovered energy release might strongly change the thermal evolution
behavior of the star.Comment: 18pages,3figures;to be accepted for publication in Physics Letters
Searching for Charged Higgs Boson in Polarized Top Quark
The charged Higgs boson is quite common in many new physics models. In this
study we examine the potential of observing a heavy charged Higgs boson in its
decay mode of top-quark and bottom-quark in the Type-II
Two-Higgs-Doublet-Model. In this model, the chirality structure of the coupling
of charged Higgs boson to the top- and bottom-quark is very sensitive to the
value of . As the polarization of the top-quark can be measured
experimentally from the top-quark decay products, one could make use of the
top-quark polarization to determine the value of . We preform a
detailed analysis of measuring top-quark polarization in the production
channels and . We calculate the helicity
amplitudes of the charged Higgs boson production and decay.Our calculation
shows that the top-quark from the charged Higgs boson decay provides a good
probe for measuring , especially for the intermediate
region. On the contrary, the top-quark produced in association with the charged
Higgs boson cannot be used to measure because its polarization is
highly contaminated by the -channel kinematics.Comment: 21 pages, 12 figures, 2 table
Visual field mean deviation and relevant factors in 928 Chinese retinitis pigmentosa patients
AIM: To investigate the associations between demographic and clinical factors with the rate of visual field mean derivation (MD) decline in retinitis pigmentosa (RP) patients.
METHODS: Correlations of MDs with the visual acuity and retinal pigmentation were analyzed in 928 RP patients. MD decreasing rate in 10y and potential influences of gender, age, family history and retinal pigmentation on the rate were explored in 201 RP patients.
RESULTS: In the 928 patients, average MD and visual acuity were -14.44±8.61 dB and 0.79±0.35 respectively and when MD was lower than -9.18 dB the visual acuity would be below 1.0 (20/20). The average MD medium between eyes with or without retinal pigmentation was -14.82 dB. In 123 non-pigmented eyes, the average MD were lower than the medium but in 153 pigmented eyes it was higher than that. In the 201 patients, the average decreasing value of MD in 10 years’ period was -8.01±3.66 dB and the value were correlated to retinal pigmentation but not to gender, age or RP family history.
CONCLUSION: The rate of MD decline in RP eyes is significantly related to retinal pigmentation. Our study demonstrates the quantitative rate of MD decline in RP patients and the value of MD could well reflect the severity of RP
Geometric bionics: Lotus effect helps polystyrene nanotube films get good blood compatibility
Various biomaterials have been widely used for manufacturing biomedical applications including artificial organs, medical devices and disposable clinical apparatus, such as vascular prostheses, blood pumps, artificial kidney, artificial hearts, dialyzers and plasma separators, which could be used in contact with blood^1^. However, the research tasks of improving hemocompatibility of biomaterials have been carrying out with the development of biomedical requirements^2^. Since the interactions that lead to surface-induced thrombosis occurring at the blood-biomaterial interface become a reason of familiar current complications with grafts therapy, improvement of the blood compatibility of artificial polymer surfaces is, therefore a major issue in biomaterials science^3^. After decades of focused research, various approaches of modifying biomaterial surfaces through chemical or biochemical methods to improve their hemocompatibility were obtained^1^. In this article, we report that polystyrene nanotube films with morphology similar to the papilla on lotus leaf can be used as blood-contacted biomaterials by virtue of Lotus effect^4^. Clearly, this idea, resulting from geometric bionics that mimicking the structure design of lotus leaf, is very novel technique for preparation of hemocompatible biomaterials
Sound absorption properties of polyurethane-based warp-knitted spacer fabric composites
Sound absorption properties of polyurethane-based warp-knitted spacer fabric composites (PWSF) have been studied. The warp-knitted spacer fabrics (WSF) are produced on a double-needle bar warp knitting machine using different structural parameters including inclination angle of spacer yarn, thickness, spacer yarn’s diameter and surface layer structure. The composites are fabricated based on a flexible polyurethane foam. Accordingly, the acoustical behaviors of composites are evaluated properly by using two-microphone transfer function techniques in impedance tube. The findings reveal that the composites possess excellent sound absorption properties and their sound absorbability can be tailored to meet the specificend-use requirements by varying the fabric structural parameters
The role and possible molecular mechanism of valproic acid in the growth of MCF-7 breast cancer cells
Aim To investigate the role of valproic acid (VPA), a class I
selective histone deacetylase inhibitor, on Michigan Cancer
Foundation (MCF)-7 breast cancer cells, named and explore
its possible molecular mechanism.
Methods MCF-7 cells were cultured with sodium valproate
(0. 5-4.0 mmol/L) for 24 h, 48 h, and 72 h in vitro, respectively.
The cell viability, apoptosis, and cell cycle were examined.
The activities and protein expressions of caspase-3,
caspase-8, and caspase-9 were subsequently assayed. Finally,
mRNA and protein expressions of cyclin A, cyclin D1,
cyclin E, and p21 were analyzed.
Results Sodium valproate suppressed MCF-7 cell growth,
induced cell apoptosis, and arrested G1 phase in a timeand
concentration- dependent manner, with the relative
cell viabilities decreased, cell apoptosis ratios increased,
and percentage of G1 phase enhanced (P < 0.05). Increased
activity of caspase-3 and caspase-9, but not caspase-8, and
increased protein levels were found under sodium valproate
(2.0 mmol/L, 48h). P21 was up-regulated and cyclin
D1 was down-regulated at both mRNA and protein levels
under sodium valproate (2.0 mmol/L, 48h)(P < 0.05), although
cyclin E and cyclin A remained changed.
Conclusion These results indicate that VPA can suppress
the growth of breast cancer MCF-7 cells by inducing apoptosis
and arresting G1 phase. Intrinsic apoptotic pathway is
dominant for VPA-induced apoptosis. For G1 phase arrest,
p21 up-regulation and down-regulation of cyclin D1 may
be the main molecular mechanism
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