33,858 research outputs found
Phenylboronic acid-diol crosslinked 6-<i>O</i>-vinylazeloyl-d-galactose nanocarriers for insulin delivery
A new block polymer named poly 3-acrylamidophenylboronic acid-b-6-O–vinylazeloyl-d-galactose (p(AAPBA-b-OVZG)) was prepared using 3-acrylamidophenylboronic acid (AAPBA) and 6-O-vinylazeloyl-D-galactose (OVZG) via a two-step procedure involving S-1-dodecyl-S-(α', α'-dimethyl-α″-acetic acid) trithiocarbonate (DDATC) as chain transfer agent, 2,2-azobisisobutyronitrile (AIBN) as initiator and dimethyl formamide (DMF) as solvent. The structures of the polymer were examined by Fourier transform infrared spectroscopy (FT-IR) and 1H NMR and the thermal stability was determined by thermal gravimetric analysis (TG/DTG). Transmission electron microscopy (TEM) and dynamic light scattering (DLS) were utilized to evaluate the morphology and properties of the p(AAPBA-b-OVZG) nanoparticles. The cell toxicity, animal toxicity and therapeutic efficacy were also investigated. The results indicate the p(AAPBA-b-OVZG) was successfully synthesized and had excellent thermal stability. Moreover, the p(AAPBA-b-OVZG) nanoparticles were submicron in size and glucose-sensitive in phosphate-buffered saline (PBS). In addition, insulin as a model drug had a high encapsulation efficiency and loading capacity and the release of insulin was increased at higher glucose levels. Furthermore, the nanoparticles showed a low-toxicity in cell and animal studies and they were effective at decreasing blood glucose levels of mice over 96 h. These p(AAPBA-b-OVZG) nanoparticles show promise for applications in diabetes treatment using insulin or other hypoglycemic proteins
Assessment of density functional methods with correct asymptotic behavior
Long-range corrected (LC) hybrid functionals and asymptotically corrected
(AC) model potentials are two distinct density functional methods with correct
asymptotic behavior. They are known to be accurate for properties that are
sensitive to the asymptote of the exchange-correlation potential, such as the
highest occupied molecular orbital energies and Rydberg excitation energies of
molecules. To provide a comprehensive comparison, we investigate the
performance of the two schemes and others on a very wide range of applications,
including the asymptote problems, self-interaction-error problems, energy-gap
problems, charge-transfer problems, and many others. The LC hybrid scheme is
shown to consistently outperform the AC model potential scheme. In addition, to
be consistent with the molecules collected in the IP131 database [Y.-S. Lin,
C.-W. Tsai, G.-D. Li, and J.-D. Chai, J. Chem. Phys., 2012, 136, 154109], we
expand the EA115 and FG115 databases to include, respectively, the vertical
electron affinities and fundamental gaps of the additional 16 molecules, and
develop a new database AE113 (113 atomization energies), consisting of accurate
reference values for the atomization energies of the 113 molecules in IP131.
These databases will be useful for assessing the accuracy of density functional
methods.Comment: accepted for publication in Phys. Chem. Chem. Phys., 46 pages, 4
figures, supplementary material include
Width-tuned magnetic order oscillation on zigzag edges of honeycomb nanoribbons
Quantum confinement and interference often generate exotic properties in
nanostructures. One recent highlight is the experimental indication of a
magnetic phase transition in zigzag-edged graphene nanoribbons at the critical
ribbon width of about 7 nm [G. Z. Magda et al., Nature \textbf{514}, 608
(2014)]. Here we show theoretically that with further increase in the ribbon
width, the magnetic correlation of the two edges can exhibit an intriguing
oscillatory behavior between antiferromagnetic and ferromagnetic, driven by
acquiring the positive coherence between the two edges to lower the free
energy. The oscillation effect is readily tunable in applied magnetic fields.
These novel properties suggest new experimental manifestation of the edge
magnetic orders in graphene nanoribbons, and enhance the hopes of graphene-like
spintronic nanodevices functioning at room temperature.Comment: 22 pages, 9 figure
Quark condensate and magnetic moment in a strong magnetic field
This paper studies the quark condensate, magnetic moment, magnetic
polarization, and magnetic susceptibility in a strong external magnetic field
by employing the Dyson-Schwinger equations (DSE). The results show that these
physical quantities as functions of the magnetic field. We note that the
quark's spin polarizations are approximately proportional to the magnetic field
magnitude. For comparison, we investigate the magnetic moments and
susceptibility of the nucleon in the constituent quark model framework and
demonstrate that both these quantities increase as the magnetic field rises.Comment: 10 pages, 5 figure
Quantum criticality, particle-hole symmetry, and duality of the plateau-insulator transition in the quantum Hall regime
We report new experimental data on the plateau-insulator transition in the
quantum Hall regime, taken from a low mobility InGaAs/InP heterostructure. By
employing the fundamental symmetries of the quantum transport problem we are
able to disentangle the universal quantum critical aspects of the
magnetoresistance data (critical indices and scaling functions) and the sample
dependent aspects due to macroscopic inhomogeneities. Our new results and
methodology indicate that the previously established experimental value for the
critical index (kappa = 0.42) resulted from an admixture of both universal and
sample dependent behavior. A novel, non-Fermi liquid value is found (kappa =
0.57) along with the leading corrections to scaling. The statement of
self-duality under the Chern Simons flux attachment transformation is verified.Comment: 4 pages, 2 figure
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