680 research outputs found
Mineral composition of hypogeous fungi in Hungary
In the course of the work, 93 samples from 17 hypogeous fungus species belonging to 6 genera were taken from various habitats in Hungary and were analysed for the concentrations of 22 elements using the inductively coupled plasma spectroscopy ICP method. All the measurements were made in three independent replications.The data were compared with the element contents of 625 epigeous fungi, previously determined using the same method. For all the genera, the elements present in the highest concentrations on a dry matter basis were potassium (6990-29590 ppm) and phosphorus (3400-9140 ppm). These were followed by the macroelements calcium (330-2190 ppm), magnesium (810-1000 ppm) and sodium (110-2990), and the microelements aluminium (30-450 ppm), zinc (60-340 ppm), iron (30-120 ppm) and copper (25-75 ppm), in different orders for each genus.Until now the element contents of fungi have mostly been analysed to determine the nutritional value of edible fungi, and the data on other elements for instance total minerals are insuffi cient for further comparisons (MATTILA et al., 2001).Very little work has been published on the mineral contents of hypogeous large fungi, despite the fact that these include commercially important species such as Tuber aestivum and T. melanosporum (IAN et al., 2003). Most of the previous papers exhibited the following characteristics: (1) some species (e.g. Terfezia species, Tuber melanosporum) were investigated more frequently, and others rarely, if at all; (2) the analyses concentrated chiefly on toxicological and/or environmental aspects; (3) measurements were only made on a few elements (important from the nutritional point of view); (4) only cultivated fungi were included in the studies. The aim of the present work was to determine the element contents of various species of hypogeous fungi in order to answer the following questions: (1) Which characteristic differences can be observed between the element contents of hypogeous and epigeous fungi? (2) Which differences characterise the element contents of various genera of hypogeous fungi? (3) Is there any signifi cant difference between the element contents of hypogeous Ascomycota and Basidiomycota genera? (4) Can any significant difference be observed between the element contents of edible and non-edible hypogeous fungi
Nonlinear Dynamics of Capacitive Charging and Desalination by Porous Electrodes
The rapid and efficient exchange of ions between porous electrodes and
aqueous solutions is important in many applications, such as electrical energy
storage by super-capacitors, water desalination and purification by capacitive
deionization (or desalination), and capacitive extraction of renewable energy
from a salinity difference. Here, we present a unified mean-field theory for
capacitive charging and desalination by ideally polarizable porous electrodes
(without Faradaic reactions or specific adsorption of ions) in the limit of
thin double layers (compared to typical pore dimensions). We illustrate the
theory in the case of a dilute, symmetric, binary electrolyte using the
Gouy-Chapman-Stern (GCS) model of the double layer, for which simple formulae
are available for salt adsorption and capacitive charging of the diffuse part
of the double layer. We solve the full GCS mean-field theory numerically for
realistic parameters in capacitive deionization, and we derive reduced models
for two limiting regimes with different time scales: (i) In the
"super-capacitor regime" of small voltages and/or early times where the porous
electrode acts like a transmission line, governed by a linear diffusion
equation for the electrostatic potential, scaled to the RC time of a single
pore. (ii) In the "desalination regime" of large voltages and long times, the
porous electrode slowly adsorbs neutral salt, governed by coupled, nonlinear
diffusion equations for the pore-averaged potential and salt concentration
Analgesic Effects of GpTx-1, PF-04856264 and CNV1014802 in a Mouse Model of NaV1.7-Mediated Pain
Loss-of-function mutations of NaV1.7 lead to congenital insensitivity to pain, a rare condition resulting in individuals who are otherwise normal except for the inability to sense pain, making pharmacological inhibition of NaV1.7 a promising therapeutic strategy for the treatment of pain. We characterized a novel mouse model of NaV1.7-mediated pain based on intraplantar injection of the scorpion toxin OD1, which is suitable for rapid in vivo profiling of NaV1.7 inhibitors. Intraplantar injection of OD1 caused spontaneous pain behaviors, which were reversed by co-injection with NaV1.7 inhibitors and significantly reduced in NaV1.7−/− mice. To validate the use of the model for profiling NaV1.7 inhibitors, we determined the NaV selectivity and tested the efficacy of the reported NaV1.7 inhibitors GpTx-1, PF-04856264 and CNV1014802 (raxatrigine). GpTx-1 selectively inhibited NaV1.7 and was effective when co-administered with OD1, but lacked efficacy when delivered systemically. PF-04856264 state-dependently and selectively inhibited NaV1.7 and significantly reduced OD1-induced spontaneous pain when delivered locally and systemically. CNV1014802 state-dependently, but non-selectively, inhibited NaV channels and was only effective in the OD1 model when delivered systemically. Our novel model of NaV1.7-mediated pain based on intraplantar injection of OD1 is thus suitable for the rapid in vivo characterization of the analgesic efficacy of NaV1.7 inhibitors
Coherent amplification of classical pion fields during the cooling of droplets of quark plasma
In the framework of the linear sigma model, we study the time evolution of a
system of classical and pion fields coupled to quarks. For this
purpose we solve numerically the classical transport equation for relativistic
quarks coupled to the nonlinear Klein-Gordon equations for the meson fields. We
examine evolution starting from variety of initial conditions corresponding to
spherical droplets of hot quark matter, which might mimic the behaviour of a
quark plasma produced in high-energy nucleus-nucleus collisions. For large
droplets we find a strong amplification of the pion field that oscillates in
time. This leads to a coherent production of pions with a particular isospin
and so would have similar observable effects to a disoriented chiral condensate
which various authors have suggested might be a signal of the chiral phase
transition. The mechanism for amplification of the pion field found here does
not rely on this phase transition and is better thought of as a "pion laser"
which is driven by large oscillations of the field.Comment: 12 TeX pages + 20 postscript figures, psfig styl
Diffuse charge and Faradaic reactions in porous electrodes
Porous electrodes instead of flat electrodes are widely used in electrochemical systems to boost storage
capacities for ions and electrons, to improve the transport of mass and charge, and to enhance reaction rates.
Existing porous electrode theories make a number of simplifying assumptions: (i) The charge-transfer rate is
assumed to depend only on the local electrostatic potential difference between the electrode matrix and the pore
solution, without considering the structure of the double layer (DL) formed in between; (ii) the charge-transfer
rate is generally equated with the salt-transfer rate not only at the nanoscale of the matrix-pore interface, but also
at the macroscopic scale of transport through the electrode pores. In this paper, we extend porous electrode theory
by including the generalized Frumkin-Butler-Volmer model of Faradaic reaction kinetics, which postulates charge
transfer across the molecular Stern layer located in between the electron-conducting matrix phase and the plane
of closest approach for the ions in the diffuse part of the DL. This is an elegant and purely local description of the
charge-transfer rate, which self-consistently determines the surface charge and does not require consideration of
reference electrodes or comparison with a global equilibrium. For the description of the DLs, we consider the
two natural limits: (i) the classical Gouy-Chapman-Stern model for thin DLs compared to the macroscopic pore
dimensions, e.g., for high-porosity metallic foams (macropores >50 nm) and (ii) a modified Donnan model for
strongly overlapping DLs, e.g., for porous activated carbon particles (micropores <2 nm). Our theory is valid
for electrolytes where both ions are mobile, and it accounts for voltage and concentration differences not only on
the macroscopic scale of the full electrode, but also on the local scale of the DL. The model is simple enough to
allow us to derive analytical approximations for the steady-state and early transients. We also present numerical
solutions to validate the analysis and to illustrate the evolution of ion densities, pore potential, surface charge,
and reaction rates in response to an applied voltage
The Large Enriched Germanium Experiment for Neutrinoless Double Beta Decay (LEGEND)
The observation of neutrinoless double-beta decay (0)
would show that lepton number is violated, reveal that neutrinos are Majorana
particles, and provide information on neutrino mass. A discovery-capable
experiment covering the inverted ordering region, with effective Majorana
neutrino masses of 15 - 50 meV, will require a tonne-scale experiment with
excellent energy resolution and extremely low backgrounds, at the level of
0.1 count /(FWHMtyr) in the region of the signal. The
current generation Ge experiments GERDA and the MAJORANA DEMONSTRATOR
utilizing high purity Germanium detectors with an intrinsic energy resolution
of 0.12%, have achieved the lowest backgrounds by over an order of magnitude in
the 0 signal region of all 0
experiments. Building on this success, the LEGEND collaboration has been formed
to pursue a tonne-scale Ge experiment. The collaboration aims to develop
a phased 0 experimental program with discovery potential
at a half-life approaching or at years, using existing resources as
appropriate to expedite physics results.Comment: Proceedings of the MEDEX'17 meeting (Prague, May 29 - June 2, 2017
Disoriented chiral condensate formation from tubes of hot quark plasma
We investigate the time evolution of a system of quarks interacting with
sigma and pion fields starting from an initial configuration consisting of a
tube of hot quark plasma undergoing a boost-invariant longitudinal expansion.
We work within the framework of the linear sigma model using classical
transport equations for the quarks coupled to the mean-field equations for the
meson fields. In certain cases we find strong amplifications of any initial
pion fields. For large-radius tubes, starting from quark densities that are
very close to critical, we find that a disoriented chiral condensate can form
in the centre of the tube. Eventually the collapse of the tube drives this
state back to the true vacuum. This process converts the disoriented
condensate, dominated by long-wavelength pion modes, into a coherent excitation
of the pion field that includes significant components with transverse momenta
of around 400 MeV. In contrast, for narrow tubes or larger initial
temperatures, amplification occurs only via the pion-laser-like mechanism found
previously for spherical systems. In addition, we find that explicit chiral
symmetry breaking significantly suppresses the formation of disoriented
condensates.Comment: 18 pages (RevTeX), 8 figures (psfig
The Majorana Project
Building a \BBz experiment with the ability to probe neutrino mass in the
inverted hierarchy region requires the combination of a large detector mass
sensitive to \BBz, on the order of 1-tonne, and unprecedented background
levels, on the order of or less than 1 count per year in the \BBz signal
region. The MAJORANA Collaboration proposes a design based on using high-purity
enriched Ge-76 crystals deployed in ultra-low background electroformed Cu
cryostats and using modern analysis techniques that should be capable of
reaching the required sensitivity while also being scalable to a 1-tonne size.
To demonstrate feasibility, the collaboration plans to construct a prototype
system, the MAJORANA DEMONSTRATOR, consisting of 30 kg of 86% enriched \Ge-76
detectors and 30 kg of natural or isotope-76-depleted Ge detectors. We plan to
deploy and evaluate two different Ge detector technologies, one based on a
p-type configuration and the other on n-type.Comment: paper submitted for the 2008 Carolina International Symposium on
Neutrino Physic
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