855 research outputs found
Metallomics in environmental and health related research: Current status and perspectives
Metals and metalloids play distinct roles in human health, either beneficial or toxic, depending on their concentrations and species. There is an increasing interest in metals uptake, trafficking, function, and exertion in microorganisms to maintain and advance human health. Metallomics, an emerging research area, focuses on elucidation of metals/metalloids location, distribution, speciation, and behavior in living organisms. This paper briefly summarized the recent progress on the methodology development of metallomics including various techniques, i. e. multiple dimensional liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICPMS), gel electrophoresis-laser ablation-inductively coupled plasma mass spectrometry (GE-LA-ICPMS), synchrotron X-ray fluorescent spectroscopy (XFS), and the applications of metallomics in environmental and health care. © 2012 The Author(s).published_or_final_versio
Quantum energy flow in mesoscopic dielectric structures
We investigate the phononic energy transport properties of mesoscopic,
suspended dielectric wires. The Landauer formula for the thermal conductance is
derived and its universal aspects discussed. We then determine the variance of
the energy current in the presence of a steady state current flow. In the final
part, some initial results are presented concerning the nature of the
temperature fluctuations of a mesoscopic electron gas thermometer due to the
absorption and emission of wire phonons.Comment: 20 pages, 2 figures. Submitted to Phys. Rev.
Widely tunable gain-switched operation of external cavity grating-coupled surface emitting laser
Widely tunable gain switching of a grating-coupled surface-emitting laser (GCSEL) has been demonstrated in a simple external cavity configuration for the first time. Pulse duration in range of 40-100ps and wavelength tuning over 100nm have been achieved. High power, tail-free optical pulses have been observed at 980nm
Reionization by active sources and its effects on the cosmic microwave background
We investigate the possible effects of reionization by active sources on the
cosmic microwave background. We concentrate on the sources themselves as the
origin of reionization, rather than early object formation, introducing an
extra period of heating motivated by the active character of the perturbations.
Using reasonable parameters, this leads to four possibilities depending on the
time and duration of the energy input: delayed last scattering, double last
scattering, shifted last scattering and total reionization. We show that these
possibilities are only very weakly constrained by the limits on spectral
distortions from the COBE FIRAS measurements. We illustrate the effects of
these reionization possibilities on the angular power spectrum of temperature
anisotropies and polarization for simple passive isocurvature models and simple
coherent sources, observing the difference between passive and active models.
Finally, we comment on the implications of this work for more realistic active
sources, such as causal white noise and topological defect models. We show for
these models that non-standard ionization histories can shift the peak in the
CMB power to larger angular scales.Comment: 21 pages LaTeX with 11 eps figures; replaced with final version
accepted for publication in Phys. Rev.
Uniaxial Phase Transition in Si : Ab initio Calculations
Based on a previously proposed thermodynamic analysis, we study the relative
stabilities of five Si phases under uniaxial compression using ab initio
methods. The five phases are diamond, beta-tin, sh, sc, and hcp structures. The
possible phase-transition patterns were investigated by considering the phase
transitions between any two chosen phases of the five phases. By analyzing the
different conributions to the relative pahse stability, we identified the most
important factors in reducing the phase-transition pressures at uniaxial
compression. We also show that it is possible to have phase transitions occur
only when the phases are under uniaxial compression, in spite of no phase
transition when under hydrostatic commpression. Taking all five phases into
consideration, the phase diagram at uniaxial compression was constructed for
pressures under 20 GPa. The stable phases were found to be diamond, beta-tin
and sh structures, i.e. the same as those when under hydrostatic condition.
According to the phase diagram, direct phase transition from the diamond to the
sh phase is possible if the applied uniaxial pressures, on increasing, satisfy
the condition of Px>Pz. Simiilarly, the sh-to-beta-tin transition on
increeasing pressures is also possible if the applied uniaxial pressures are
varied from the condition of Px>Pz, on which the phase of sh is stable, to that
of Px<Pz, on which the beta-tin is stable
Genetic and bioinformatic analyses of the expression and function of PI3K regulatory subunit PIK3R3 in an Asian patient gastric cancer library
10.1186/1755-8794-5-34BMC Medical Genomics5
Double quantum dot turnstile as an electron spin entangler
We study the conditions for a double quantum dot system to work as a reliable
electron spin entangler, and the efficiency of a beam splitter as a detector
for the resulting entangled electron pairs. In particular, we focus on the
relative strengths of the tunneling matrix elements, the applied bias and gate
voltage, the necessity of time-dependent input/output barriers, and the
consequence of considering wavepacket states for the electrons as they leave
the double dot to enter the beam splitter. We show that a double quantum dot
turnstile is, in principle, an efficient electron spin entangler or
entanglement filter because of the exchange coupling between the dots and the
tunable input/output potential barriers, provided certain conditions are
satisfied in the experimental set-up.Comment: published version; minor error correcte
Apremilast, an oral phosphodiesterase 4 (PDE4) inhibitor, in patients with moderate to severe plaque psoriasis: Results of a phase III, randomized, controlled trial (Efficacy and Safety Trial Evaluating the Effects of Apremilast in Psoriasis [ESTEEM] 1)
BackgroundApremilast works intracellularly to regulate inflammatory mediators.ObjectiveESTEEM 1 evaluated efficacy/safety of apremilast at 30 mg twice a day for moderate to severe plaque psoriasis.MethodsThis phase III, multicenter, double-blind, placebo-controlled study randomized adults (2:1) to apremilast or placebo. At week 16, the placebo group switched to apremilast through week 32, followed by a randomized treatment withdrawal phase to week 52. Binary end points were analyzed using χ2 test; continuous end points used analysis of covariance.ResultsIn all, 844 patients were randomized (n = 282, placebo; n = 562, apremilast). At week 16, significantly more patients taking apremilast achieved 75% or greater reduction from baseline Psoriasis Area and Severity Index score (PASI-75) (33.1%) versus placebo (5.3%, P < .0001; primary end point). Most (61.0%) patients rerandomized to apremilast at week 32 achieved PASI-75 at week 52 versus 11.7% rerandomized to placebo. Of patients rerandomized to apremilast at week 32, mean percentage change from baseline PASI score was −88% to −81% (weeks 32-52). During the placebo-controlled period, 55.7% and 69.3% of patients randomized to placebo and apremilast, respectively, had 1 or more adverse events. Most adverse events were mild/moderate in severity. No new significant adverse events emerged with continued apremilast exposure versus the placebo-controlled period.LimitationsData were limited to 52 weeks and may not generalize to nonplaque psoriasis.ConclusionsApremilast was effective in moderate to severe plaque psoriasis
Use of the Generalized Gradient Approximation in Pseudopotential Calculations of Solids
We present a study of the equilibrium properties of -bonded solids within
the pseudopotential approach, employing recently proposed generalized gradient
approximation (GGA) exchange correlation functionals. We analyze the effects of
the gradient corrections on the behavior of the pseudopotentials and discuss
possible approaches for constructing pseudopotentials self-consistently in the
context of gradient corrected functionals. The calculated equilibrium
properties of solids using the GGA functionals are compared to the ones
obtained through the local density approximation (LDA) and to experimental
data. A significant improvement over the LDA results is achieved with the use
of the GGA functionals for cohesive energies. For the lattice constant, the
same accuracy as in LDA can be obtained when the nonlinear coupling between
core and valence electrons introduced by the exchange correlation functionals
is properly taken into account. However, GGA functionals give bulk moduli that
are too small compared to experiment.Comment: 15 pages, latex, no figure
Automatic Structure Detection in Constraints of Tabular Data
Abstract. Methods for the protection of statistical tabular data—as controlled tabular adjustment, cell suppression, or controlled rounding— need to solve several linear programming subproblems. For large multi-dimensional linked and hierarchical tables, such subproblems turn out to be computationally challenging. One of the techniques used to reduce the solution time of mathematical programming problems is to exploit the constraints structure using some specialized algorithm. Two of the most usual structures are block-angular matrices with either linking rows (primal block-angular structure) or linking columns (dual block-angular structure). Although constraints associated to tabular data have intrin-sically a lot of structure, current software for tabular data protection neither detail nor exploit it, and simply provide a single matrix, or at most a set of smallest submatrices. We provide in this work an efficient tool for the automatic detection of primal or dual block-angular struc-ture in constraints matrices. We test it on some of the complex CSPLIB instances, showing that when the number of linking rows or columns is small, the computational savings are significant
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