6,184 research outputs found
Recommended from our members
The first international workshop on the role and impact of mathematics in medicine: a collective account
The First International Workshop on The Role and Impact of Mathematics in Medicine (RIMM) convened in Paris in June 2010. A broad range of researchers discussed the difficulties, challenges and opportunities faced by
those wishing to see mathematical methods contribute to improved medical outcomes. Finding mechanisms for inter-
disciplinary meetings, developing a common language, staying focused on the medical problem at hand, deriving
realistic mathematical solutions, obtainin
Recommended from our members
Cryo-EM structure of a fungal mitochondrial calcium uniporter.
The mitochondrial calcium uniporter (MCU) is a highly selective calcium channel localized to the inner mitochondrial membrane. Here, we describe the structure of an MCU orthologue from the fungus Neosartorya fischeri (NfMCU) determined to 3.8âĂ
resolution by phase-plate cryo-electron microscopy. The channel is a homotetramer with two-fold symmetry in its amino-terminal domain (NTD) that adopts a similar structure to that of human MCU. The NTD assembles as a dimer of dimers to form a tetrameric ring that connects to the transmembrane domain through an elongated coiled-coil domain. The ion-conducting pore domain maintains four-fold symmetry, with the selectivity filter positioned at the start of the pore-forming TM2 helix. The aspartate and glutamate sidechains of the conserved DIME motif are oriented towards the central axis and separated by one helical turn. The structure of NfMCU offers insights into channel assembly, selective calcium permeation, and inhibitor binding
ASSESSMENT OF PROCEDURAL ASPECTS AND QUALITY CONTROL IN HUMAN PLACENTAL RNA ISOLATION PROTOCOLS
poster abstractHigh quality RNA is of paramount importance in accurately interpreting gene expression changes in the placenta throughout pregnancy, as well as in common placental pathologies. The purpose of this study was to develop a standard operating procedure for the collection of human placental tissue and isolation of high quality RNA for pregnancy-related molecular studies. To accomplish this task, we compared several different parameters to minimize RNA degradation, including preservation (liquid nitrogen vs. RNAlater), dis-ruption (mortar/pestle vs. homogenization), and isolation (Trizol vs. RNeasy). We performed 150 RNA isolations from 30 term placentas. The overall yield was 365 ± 197 ng RNA per mg of tissue. The A260/280 ratio for all samples was 2.11 ± 0.1 (mean ± s.d.) and the RQI was 7.1 ± 1.4. No significant differences in RNA purity, yield, or quality were observed between different placental collections or RNA isolation techniques. However, poor RQI values of 2.7 to 3.3 were obtained after brief thawing of frozen placental samples. We also compared storage of RNAlater stabilized tissue at 4 de-grees or room temperature for 1 day, 7 days, and 30 days. The integrity of RNA stored at room temperature for 1 day was significantly better (Pâč0.05 RQI 7.3 ± 0.58, mean ± s.d) than RNA stored at room temperature for 30 days (RQI 5.0 ±1.2, mean ± s.d). The results of these studies will be useful for establishing standard procedures for placenta collection for pregnancy biobanks
The transition temperature of the dilute interacting Bose gas
We show that the critical temperature of a uniform dilute Bose gas must
increase linearly with the s-wave scattering length describing the repulsion
between the particles. Because of infrared divergences, the magnitude of the
shift cannot be obtained from perturbation theory, even in the weak coupling
regime; rather, it is proportional to the size of the critical region in
momentum space. By means of a self-consistent calculation of the quasiparticle
spectrum at low momenta at the transition, we find an estimate of the effect in
reasonable agreement with numerical simulations.Comment: 4 pages, Revtex, to be published in Physical Review Letter
Lyman alpha emitting galaxies at 0.2 < z < 0.35 from GALEX spectroscopy
The GALEX (Galaxy Evolution Explorer) spectroscopic survey mode, with a
resolution of about 8 A in the FUV (1350 - 1750 A) and about 20 A in the NUV
(1950 - 2750 A) is used for a systematic search of Ly-a emitting galaxies at
low redshift. This aims at filling a gap between high-redshift surveys and a
small set of objects studied in detail in the nearby universe. A blind search
of 7018 spectra extracted in 5 deep exposures (5.65 sq.deg) has resulted in 96
Ly-a emitting galaxy candidates in the FUV domain, after accounting for
broad-line AGNs. The Ly-a EWs (equivalent width) are consistent with stellar
population model predictions and show no trends as a function of UV color or UV
luminosity, except a possible decrease in the most luminous that may be due to
small-number statistics. Their distribution in EW is similar to that at z about
3 but their fraction among star-forming galaxies is smaller. Avoiding uncertain
candidates, a sub-sample of 66 objects in the range 0.2 < z < 0.35 has been
used to build a Ly-a LF (luminosity function). The incompleteness due to
objects with significant Ly-a emission but a UV continuum too low for spectral
extraction has been evaluated. A comparison with H-a LF in the same redshift
domain is consistent with an average Ly-a/H-a of about 1 in about 15 % of the
star-forming galaxies. A comparison with high-redshift Ly-a LFs implies an
increase of the Ly-a luminosity density by a factor of about 16 from z about
0.3 to z about 3. By comparison with the factor 5 increase of the UV luminosity
density in the same redshift range, this suggests an increase of the average
Ly-a escape fraction with redshift.Comment: 18 pages, 9 figures, accepted for publication in Ap
Strangeness Conservation in Hot Nuclear Fireballs
A constraint between thermal fireball parameters arises from the requirement
that the balance of strangeness in a fireball is (nearly) zero. We study the
impact of this constraint on (multi-)strange (anti-)baryon multiplicities and
compare the hadron gas and quark-gluon plasma predictions. We explore the
relation between the entropy content and particle multiplicities and show that
the data are compatible with the quark-gluon plasma hypothesis, but appear to
be inconsistent with the picture of an equilibrated hadron gas fireball. We
consider the implications of the results on the dynamics of evolution and decay
of the particle source.Comment: 35 pages, 11 postscript figures, report PAR/LPTHE/92--2
Radiatively-induced Magnetic moment in four-dimensional anisotropic QED in an external magnetic field
We discuss one-loop radiatively-induced magnetic moment in four-dimensional
quantum electrodynamics (QED) with anisotropic coupling, and examine various
cases which may be of interest in effective gauge theories of antiferromagnets,
whose planar limit coresponds to highly anisotropic QED couplings. We find a
different scaling with the magnetic field intensity in case there are extra
statistical gauge interactions in the model with spontaneous symmetry breaking.
Such a case is encountered in the CP-1 sigma-model sector of effective
spin-charge separated gauge theories of antiferromagnetic systems. Our work
provides therefore additional ways of possible experimental probing of the
gauge nature of such systems.Comment: 14 pages Latex, no figure
- âŠ