2,932 research outputs found
Compartmentalized, multiphasic nanocolloids with potential applications in drug delivery and biomedical imaging
Nanoparticles are excellent candidates for drug delivery or biomedical imaging, because they often exhibit superb tuneability of critical properties, such as size, surface characteristics, degradation rate, and therefore drug release rates. We have recently developed a route towards fabrication of sub-micron particles that relies on electrohydrodynamic co-jetting. In this process, fluid manipulation in an electrical field is used to fabricate large quantities of multi-compartment particles, where individual compartments can be independently loaded with different drugs or selectively surface-modified. In this contribution, aspects of multifunctional particles for biomedical applications are reviewed and a specific focus is given to recent progress with compartmentalized, multiphasic nanocolloids in our laboratory.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/57529/1/1008_ftp.pd
Nuclear mass table in density functional approach inspired by neutron-star observations
Background: Nuclear energy-density functional (EDF) approach has been widely
used to describe nuclear-matter equations of state (EoS) and properties of
finite nuclei. Recent advancements in neutron-star (NS) observations have put
constraints on the nuclear EoS. The Korea-IBS-Daegu-SKKU (KIDS) functional has
been then developed to satisfy the NS observations and applied to homogeneous
nuclear matter and spherical nuclei. Purpose: We examine the performance of the
KIDS functional by calculating the masses and charge radii of even-even nuclei
towards the drip lines. Method: The Kohn-Sham-Bogoliubov equation is solved by
taking into account the axial deformation. Results: The root-mean-square
deviation of the binding energy and the charge radius for the KIDS functional
is 4.5--5.1 MeV and 0.03--0.04 fm, which is comparable to that for existing
EDFs. The emergence and development of nuclear deformation in open-shell nuclei
are well described. The location of the neutron drip line is according to the
nuclear-matter parameter characterizing the low-mass NS. Conclusions: The
NS-observation-inspired EDF offers a reasonable reproduction of the structures
of finite nuclei. A future global optimization including more nuclear data will
give better accuracy and high predictive power of neutron-rich nuclei.Comment: 9 pages, 6 figures, and 2 table
Influences of small-scale oscillations on growth inhibition and ultrastructural changes of Microcystis cells
We investigated the effects of small-scale oscillation (SSO) on toxic Microcystis cells. The oscillating device was made of silicon with two axes that had a diameter of similar to 40 mm, and a frequency of 2.5 Hz was observed at 150 rpm. The SSO was effective in inhibiting Microcystis growth. Microcystin release was not observed, whereas cell density barely increased in the oscillating group. Cell size and morphology of the oscillating group were no different from the control group. However, cell quotas of chl.a and microcystin in the oscillating group were half the level of the control group. Crucially, a number of large-sized holes were observed and layered long linear thylakoids were rarely observed in the oscillating group. Therefore, SSO was found to be very effective in Microcystis growth inhibition, and it caused ultrastructural changes without damage to the cell membrane and subsequent microcystin release.ArticleJournal of Environmental Science and Health, Part A.53(13):1161-1166(2018)journal articl
Kinematics and excitation of the ram pressure stripped ionized gas filaments in the Coma cluster of galaxies
We present the results of deep imaging and spectroscopic observations of very
extended ionized gas (EIG) around four member galaxies of the Coma cluster of
galaxies: RB199, IC4040, GMP2923 and GMP3071. The EIGs were serendipitously
found in an H-alpha narrow band imaging survey of the central region of the
Coma cluster. The relative radial velocities of the EIGs with respect to the
systemic velocities of the parent galaxies from which they emanate increase
almost monotonically with the distance from the nucleus of the respective
galaxies, reaching -400 - -800 km/s at around 40 - 80 kpc from the galaxies.
The one-sided morphologies and the velocity fields of the EIGs are consistent
with the predictions of numerical simulations of ram pressure stripping. We
found a very low-velocity filament (v_rel = -1300 km/s) at the southeastern
edge of the disk of IC4040. Some bright compact knots in the EIGs of RB199 and
IC4040 exhibit blue continuum and strong H-alpha emission. The equivalent
widths of the H-alpha emission exceed 200 A, and are greater than 1000 A for
some knots. The emission line intensity ratios of the knots are basically
consistent with those of sub-solar abundance HII regions. These facts indicate
that intensive star formation occurs in the knots. Some filaments, including
the low velocity filament of the IC4040 EIG, exhibit shock-like emission line
spectra, suggesting that shock heating plays an important role in ionization
and excitation of the EIGs.Comment: Accepted for publication in The Astrophysical Journal. 14 pages, 23
figures, emulateapj forma
String Junction Transitions in the Moduli Space of N=2 SYM
The string theory description of BPS states in D-brane world-volume field
theories may undergo transitions from open strings to string webs, as well as
between different string webs, as one moves in the field theory moduli space.
These transitions are driven by the string creation phenomenon. We demonstrate
such transitions in the D3-brane realization of N=2 SU(2) Super-Yang-Mills
theory.Comment: 15 pages LaTex, 10 eps figure
The Jeju Weasel, Mustela sibilica quelpartis, A New Definitive Host for Gnathostoma nipponicum Yamaguti, 1941
Adult gnathostomes were discovered in the stomach of the Jeju weasel, Mustela sibilica quelpartis, road-killed in Jeju-do (Province). Their morphological characters were examined to identify the species. Total 50 gnathostome adults were collected from 6 out of 10 weasels examined. In infected weasels, 4-6 worms were grouped and embedded in each granulomatous gastric tumor, except 1 weasel. Male worms were 25.0Ă1.4 mm in average size, and had a tail with pedunculate papillae, a spicule, and minute tegumental spines. Females were 40.0Ă2.5 mm in average size, and had a tail without tegumental spines. Pointed and posteriorly curved hooklets were arranged in 8-10 rows on the head bulb. Tegumental spines were distributed from behind the head bulb to the middle portion of the body. The spines were different in size and shape by the distribution level of the body surface. Fertilized eggs were 65.5Ă38.9 ”m in average size, and had a mucoid plug at 1 pole. These gnathostomes from Jeju weasels were identified as Gnathostoma nipponicum Yamaguti, 1941. By the present study, it was confirmed for the first time that G. nipponicum is distributed in Jeju-do, the Republic of Korea, and the Jeju weasel, M. sibilica quelpartis, plays a crucial role for its definitive host
XMM-Newton observations expose AGN in apparently normal galaxies
We have performed a detailed analysis of 3 optically normal galaxies
extracted from the XMM Bright Serendipitous Source Sample. Thanks to the good
statistics of the XMM-Newton data, we have unveiled the presence of an AGN in
all of them. In particular, we detect both X-ray obscured (N_H>10^{22} cm^{-2})
and unobscured (N_H<10^{22} cm^{-2}) AGN with intrinsic 2--10 keV luminosities
in the range between 10^{42} -- 10^{43} erg s^{-1}. We find that the X-ray and
optical properties of the sources discussed here could be explained assuming a
standard AGN hosted by galaxies with magnitudes M_R<M^*, taking properly into
account the absorption associated with the AGN, the optical faintness of the
nuclear emission with respect to the host galaxy, and the inadequate set--up
and atmospheric conditions during the optical spectroscopic observations. Our
new spectroscopic observations have revealed the expected AGN features also in
the optical band. These results clearly show that optical spectroscopy
sometimes can be inefficient in revealing the presence of an AGN, which instead
is clearly found from an X-ray spectroscopic investigation. This remarks the
importance of being careful in proposing the identification of X-ray sources
(especially at faint fluxes) when only low quality optical spectra are in hand.
This is particularly important for faint surveys (such as those with XMM-Newton
and Chandra), in which optically dull but X-ray active objects are being found
in sizeable numbers.Comment: Accepted for publication on A&A; 11 pages, 8 figure
Secular Instability of g-Modes in Rotating Neutron Stars
Gravitational radiation tends to drive gravity modes in rotating neutron
stars unstable. For an inviscid star, the instability sets in when the rotation
frequency is about 0.7 times the corresponding mode frequency of the
nonrotating star. Neutron stars with spin frequencies \go 100 Hz are
susceptible to this instability, with growth time of order years. However, it
is likely that viscous dissipation suppresses the instability except for a
narrow range of temperatures around K. We also show that the viscosity
driven instability of g-modes is absent.Comment: 8 pages, 5 figures; MNRAS, in press. 2 figures added; More details
are given for the mode propertie
R-modes of a neutron star with a magnetic dipole field
We study -modes of a rotating magnetized neutron star, assuming a magnetic
dipole field whose axis is aligned with the axis of rotation. We approach the
problem by applying a singular perturbation theory to the oscillations of
rotating stars. In this treatment, we divide the star into a thin surface
magnetic layer and a non-magnetic core. We integrate linearized ideal MHD
equations in the surface magnetic layer and non-magnetic oscillation equations
in the core, and match the two integrations at the interface to obtain a
complete solution. For a polytropic neutron star model of mass
and radius cm, the magnetic dipole field becomes effective on the modal
properties of the -modes only when the field strength is much greater
than G. We also find that the damping effects caused by very short
magnetic perturbations in the surface layer are not important for the -mode
instability of rapidly rotating neutron stars if the field strength is
smaller than G.Comment: Accepted for publication in M
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