726 research outputs found
Elastomeric membrane valves in a disc
We present elastomeric membrane valves integrated into a centrifugal microfluidic platform for precise control of fluid on a disc. The amount of the fluid passing through the valves, which depends on the rotating speed of the disc and the membrane thickness, has been characterized, and could be precisely controlled by tuning the disc motion.close131
Short Term Effect and Safety of Antidiuretic Hormone in the Patients with Nocturia
Purpose To investigate the short-term safety of antidiuretic hormone in elderly patients with nocturnal polyuria, focus on hyponatremia and others electrolytes disturbances and to assess short-term effects on nocturnal urine output and number of nocturnal voids. Methods Between June 2005 and August 2006, a total of 34 patients with nocturnal polyuria were orally administered 0.2 mg desmopressin tablet at bedtime for two weeks. Serum sodium, others electrolytes, urine sodium and urine osmolarity were assessed in the third days, one week and two weeks after treatment with desmopressin and compared adult group (<65 years of age) with elderly group (≥65 years of age). We assessed the effect of desmopressin using a frequency-volume charts and analysed. Results In total 34 patients (20 adult, 14 elderly) were analyzed. Desmopressin treatment did not significantly change serum and urine electrolytes include soduim concentration in elderly patients comparied with adult patients. Serum sodium concentration below normal range was recorded in 2 patients in elderly group, but no serious adverse events occurred and recovered without sequelae. The mean number of nocturnal voids decresed (54% reduction) and nocturnal urine output decreased (57% reduction) after using desmopressin. Conclusions Desmopressin was well tolerated and effective in elderly patients with nocturnal polyuria without clinically significant hyponatremia
Two distinct red giant branch populations in the globular cluster NGC 2419 as tracers of a merger event in the Milky Way
Recent spectroscopic observations of the outer halo globular cluster (GC) NGC
2419 show that it is unique among GCs, in terms of chemical abundance patterns,
and some suggest that it was originated in the nucleus of a dwarf galaxy. Here
we show, from the Subaru narrow-band photometry employing a calcium filter,
that the red giant-branch (RGB) of this GC is split into two distinct
subpopulations. Comparison with spectroscopy has confirmed that the redder RGB
stars in the [=(Ca] index are enhanced in [Ca/H] by 0.2
dex compared to the bluer RGB stars. Our population model further indicates
that the calcium-rich second generation stars are also enhanced in helium
abundance by a large amount (Y = 0.19). Our photometry, together with
the results for other massive GCs (e.g., Cen, M22, and NGC 1851),
suggests that the discrete distribution of RGB stars in the index might be
a universal characteristic of this growing group of peculiar GCs. The planned
narrow-band calcium photometry for the Local Group dwarf galaxies would help to
establish an empirical connection between these GCs and the primordial building
blocks in the hierarchical merging paradigm of galaxy formation.Comment: 4 pages, 4 figures, 1 table, accepted for the publication in ApJ
Protein-Ligand Interactions at Poly(amidoamine) Dendrimer Monolayers on Gold
Avidin-biotin interactions as a typical protein-ligand model were investigated on the monolayers of a fourth-generation poly(amidoamine) dendrimer that were constructed on the self-assembled monolayers (SAMs) of 11-mercaptoundecanoic acid (MUA) on gold. Surface plasmon resonance (SPR) spectroscopic analysis revealed a resonance angle shift of 0.34°( 0.03°for the formation of dendrimer monolayers on reactive SAMs, which indicates that about 89% of the gold surface is covered with dendrimer molecules. The dendrimer monolayers were functionalized with biotin, and the efficacy of dendrimer monolayers as a biomolecular interface was evaluated in terms of the surface density of biotin ligands and the avidin binding level. For comparisons, the mixed SAMs and polymeric layers of poly-L-lysine (PLL) on MUA SAMs were prepared and examined by a similar procedure. The specific binding of avidin to the biotinylated dendrimer monolayers approached a surface density of 5.0 ( 0.2 ng‚mm -2 , which corresponds to about 88% surface coverage by avidin, showing a much higher level than those from mixed SAMs (2.3 ( 0.1 ng‚mm -2 ) and PLL layers (3.2 ( 0.2 ng‚mm -2 ). Interestingly, the fully biotinylated dendrimer monolayers gave rise to efficient avidin-biotin interactions, resulting in about 80% of the maximum avidin binding level, even under the condition that a serious steric hindrance would occur due to densely packed biotin ligands. These results strongly imply that efficient avidin-biotin interaction originates from a structural feature of dendrimer monolayers such as a surface exposure of derivatized biotin ligands and a corrugated surface
Nonlinear Color-Metallicity Relations of Globular Clusters. III. On the Discrepancy in Metallicity between Globular Cluster Systems and their Parent Elliptical Galaxies
One of the conundrums in extragalactic astronomy is the discrepancy in
observed metallicity distribution functions (MDFs) between the two prime
stellar components of early-type galaxies-globular clusters (GCs) and halo
field stars. This is generally taken as evidence of highly decoupled
evolutionary histories between GC systems and their parent galaxies. Here we
show, however, that new developments in linking the observed GC colors to their
intrinsic metallicities suggest nonlinear color-to-metallicity conversions,
which translate observed color distributions into strongly-peaked, unimodal
MDFs with broad metal-poor tails. Remarkably, the inferred GC MDFs are similar
to the MDFs of resolved field stars in nearby elliptical galaxies and those
produced by chemical evolution models of galaxies. The GC MDF shape,
characterized by a sharp peak with a metal-poor tail, indicates a virtually
continuous chemical enrichment with a relatively short timescale. The
characteristic shape emerges across three orders of magnitude in the host
galaxy mass, suggesting a universal process of chemical enrichment among
various GC systems. Given that GCs are bluer than field stars within the same
galaxy, it is plausible that the chemical enrichment processes of GCs ceased
somewhat earlier than that of field stellar population, and if so, GCs
preferentially trace the major, vigorous mode of star formation events in
galactic formation. We further suggest a possible systematic age difference
among GC systems, in that the GC systems in more luminous galaxies are older.
This is consistent with the downsizing paradigm of galaxies and supports
additionally the similar nature shared by GCs and field stars. Our findings
suggest that GC systems and their parent galaxies have shared a more common
origin than previously thought, and hence greatly simplify theories of galaxy
formation.Comment: 55 pages, 7 figures, 5 tables; Accepted for publication in Ap
Realization of giant magnetoelectricity in helimagnets
We show that low field magnetoelectric (ME) properties of helimagnets
Ba0.5Sr1.5Zn2(Fe1-xAlx)12O22 can be efficiently tailored by Al-substitution
level. As x increases, the critical magnetic field for switching electric
polarization is systematically reduced from ~1 T down to ~1 mT, and the ME
susceptibility is greatly enhanced to reach a giant value of 2.0 x 10^4 ps/m at
an optimum x = 0.08. We find that control of nontrivial orbital moment in the
octahedral Fe sites through the Al-substitution is crucial for fine tuning of
magnetic anisotropy and obtaining the conspicuously improved ME
characteristics
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