373 research outputs found
A novel multifunctional biomedical material based on polyacrylonitrile:preparation and characterization
Wet spun microfibers have great potential in the design of multifunctional controlled release materials. Curcumin (Cur) and vitamin E acetate (Vit. E Ac) were used as a model drug system to evaluate the potential application of the drug-loaded microfiber system for enhanced delivery. The drugs and polyacrylonitrile (PAN) were blended together and spun to produce the target drug-loaded microfiber using an improved wet-spinning method and then the microfibers were successfully woven into fabrics. Morphological, mechanical properties, thermal behavior, drug release performance characteristics, and cytocompatibility were determined. The drug-loaded microfiber had a lobed “kidney” shape with a height of 50 ~ 100 μm and width of 100 ~ 200 μm. The addition of Cur and Vit. E Ac had a great influence on the surface and cross section structure of the microfiber, leading to a rough surface having microvoids. X-ray diffraction and Fourier transform infrared spectroscopy indicated that the drugs were successfully encapsulated and dispersed evenly in the microfilament fiber. After drug loading, the mechanical performance of the microfilament changed, with the breaking strength improved slightly, but the tensile elongation increased significantly. Thermogravimetric results showed that the drug load had no apparent adverse effect on the thermal properties of the microfibers. However, drug release from the fiber, as determined through in-vitro experiments, is relatively low and this property is maintained over time. Furthermore, in-vitro cytocompatibility testing showed that no cytotoxicty on the L929 cells was found up to 5% and 10% respectively of the theoretical drug loading content (TDLC) of curcumin and vitamin E acetate. This study provides reference data to aid the development of multifunctional textiles and to explore their use in the biomedical material field
Extended dissipaton equation of motion for electronic open quantum systems: Application to the Kondo impurity model
In this paper, we present an extended dissipaton equation of motion for
studying the dynamics of electronic impurity systems. Compared with the
original theoretical formalism, the quadratic couplings are introduced into the
Hamiltonian accounting for the interaction between the impurity and its
surrounding environment. By exploiting the quadratic dissipaton algebra, the
proposed extended dissipaton equation of motion offers a powerful tool for
studying the dynamical behaviors of electronic impurity systems, particularly
in situations where nonequilibrium and strongly correlated effects play
significant roles. Numerical demonstrations are carried out to investigate the
temperature dependence of the Kondo resonance in the Kondo impurity model.Comment: 6 pages, 1 figur
Half-Quantized Hall Effect at the Parity-Invariant Fermi Surface
Condensed matter realization of a single Dirac cone of fermions in two
dimensions is a long-standing issue. Here we report the discovery of a single
gapless Dirac cone of half-quantized Hall conductance in a magnetically-doped
topological insulator heterostructure. It demonstrates that the Hall
conductance is half-quantized in the unit e^{2}/h when the parity symmetry is
invariant near the Fermi surface. The gapless Dirac point is stable and
protected by the local parity symmetry and the topologically nontrivial band
structure of the topological insulator. The one-half Hall conductance observed
in a recent experiment [Mogi et al, Nat. Phys. 18, 390 (2022)] is attributed to
the existence of the gapless Dirac cone. The results suggest a condensed matter
realization of a topological phase with a one-half topological invariant.Comment: 6 pages with 4 figure
Assessment of thyroid function during pregnancy: the advantage of self-sequential longitudinal reference intervals
Effect of Xinyue capsules on patients with coronary heart disease after percutaneous coronary intervention: study protocol for a randomized controlled trial
Case report form 2014.3.4R2. (PDF 1119 kb
GeV antiproton/gamma-ray excesses and the -boson mass anomaly: three faces of GeV dark matter particle?
For the newly discovered -boson mass anomaly, one of the simplest dark
matter (DM) models that can account for the anomaly without violating other
astrophysical/experimental constraints is the inert two Higgs doublet model, in
which the DM mass () is found to be within GeV. In this
model, the annihilation of DM via and would
produce antiprotons and gamma rays, and may account for the excesses identified
previously in both particles. Motivated by this, we re-analyze the AMS-02
antiproton and Fermi-LAT Galactic center gamma-ray data. For the antiproton
analysis, the novel treatment is the inclusion of the charge-sign-dependent
three-dimensional solar modulation model as constrained by the time-dependent
proton data. We find that the excess of antiprotons is more distinct than
previous results based on the force-field solar modulation model. The
interpretation of this excess as the annihilation of () requires a DM mass of () GeV and a
velocity-averaged cross section of . As for the
-ray data analysis, rather than adopting the widely-used spatial
template fitting, we employ an orthogonal approach with a data-driven spectral
template analysis. The fitting to the GeV -ray excess yields DM model
parameters overlapped with those to fit the antiproton excess via the
channel. The consistency of the DM particle properties required to account for
the -boson mass anomaly, the GeV antiproton excess, and the GeV -ray
excess suggest a common origin of them.Comment: 8 page
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