549 research outputs found
Recombinant biologic products versus nutraceuticals from plants - a regulatory choice?
Biotechnology has transformed the potential for plants to be a manufacturing source of pharmaceutical compounds. Now, with transgenic and transient expression techniques, virtually any biologic, including vaccines and therapeutics, could be manufactured in plants. However, uncertainty over the regulatory path for such new pharmaceuticals has been a deterrent. Consideration has been given to using alternative regulatory paths, including those for nutraceuticals or cosmetic agents. This review will consider these possibilities, and discuss the difficulties in establishing regulatory guidelines for new pharmaceutical manufacturing technologies
Neutrino Condensate as Origin of Dark Energy
We propose a new solution to the origin of dark energy. We suggest that it
was created dynamically from the condensate of a singlet neutrino at a late
epoch of the early Universe through its effective self interaction. This
singlet neutrino is also the Dirac partner of one of the three observed
neutrinos, hence dark energy is related to neutrino mass. The onset of this
condensate formation in the early Universe is also related to matter density
and offers an explanation of the coincidence problem of why dark energy (70%)
and total matter (30%) are comparable at the present time. We demonstrate this
idea in a model of neutrino mass with (right-handed) singlet neutrinos and a
singlet scalar.Comment: 5 pages, no figure
Scalar Quantum Field Theory in Disordered Media
A free massive scalar field in inhomogeneous random media is investigated.
The coefficients of the Klein-Gordon equation are taken to be random functions
of the spatial coordinates. The case of an annealed-like disordered medium,
modeled by centered stationary and Gaussian processes, is analyzed. After
performing the averages over the random functions, we obtain the two-point
causal Green's function of the model up to one-loop. The disordered scalar
quantum field theory becomes qualitatively similar to a
self-interacting theory with a frequency-dependent coupling
The Bulk Channel in Thermal Gauge Theories
We investigate the thermal correlator of the trace of the energy-momentum
tensor in the SU(3) Yang-Mills theory. Our goal is to constrain the spectral
function in that channel, whose low-frequency part determines the bulk
viscosity. We focus on the thermal modification of the spectral function,
. Using the operator-product expansion we give
the high-frequency behavior of this difference in terms of thermodynamic
potentials. We take into account the presence of an exact delta function
located at the origin, which had been missed in previous analyses. We then
combine the bulk sum rule and a Monte-Carlo evaluation of the Euclidean
correlator to determine the intervals of frequency where the spectral density
is enhanced or depleted by thermal effects. We find evidence that the thermal
spectral density is non-zero for frequencies below the scalar glueball mass
and is significantly depleted for .Comment: (1+25) pages, 6 figure
On thermodynamics of N=6 superconformal Chern-Simons theory
We study thermodynamics of N=6 superconformal Chern-Simons theory by
computing quantum corrections to the free energy. We find that in weakly
coupled ABJM theory on R(2) x S(1), the leading correction is non-analytic in
the 't Hooft coupling lambda, and is approximately of order lambda^2
log(lambda)^3. The free energy is expressed in terms of the scalar thermal mass
m, which is generated by screening effects. We show that this mass vanishes to
1-loop order. We then go on to 2-loop order where we find a finite and positive
mass squared m^2. We discuss differences in the calculation between Coulomb and
Lorentz gauge. Our results indicate that the free energy is a monotonic
function in lambda which interpolates smoothly to the N^(3/2) behaviour at
strong coupling.Comment: 29 pages. v2: references added. v3: minor changes, references added,
published versio
Second-Order Scaling in the Two-Flavor QCD Chiral Transition
Scaling behavior is analyzed for the two-flavor QCD lattice gauge theory
chiral transition. Leading scaling behavior and correction to leading scaling
from lattice spacing effects are examined for the quark condensate. Scaling
predictions under the assumption of quark mass dominance are tested for the
longitudinal correlation length. Second order scaling behavior is consistent
with present data.Comment: 8 pages, 1 figure , Phys. Rev D, in press 199
Friedel Oscillations in Holographic Metals
In this article we study the conditions under which holographic metallic
states display Friedel oscillations. We focus on systems where the bulk charge
density is not hidden behind a black hole horizon. Understanding holographic
Friedel oscillations gives a clean way to characterize the boundary system,
complementary to probe fermion calculations. We find that fermions in a "hard
wall" AdS geometry unambiguously display Friedel oscillations. However, similar
oscillations are washed out for electron stars, suggesting a smeared continuum
of Fermi surfaces.Comment: 26 pages, 5 figure
Can We Really Prevent Suicide?
Every year, suicide is among the top 20 leading causes of death globally for all ages. Unfortunately, suicide is difficult to prevent, in large part because the prevalence of risk factors is high among the general population. In this review, clinical and psychological risk factors are examined and methods for suicide prevention are discussed. Prevention strategies found to be effective in suicide prevention
include means restriction, responsible media coverage, and general public education, as well identification methods such as screening, gatekeeper training, and primary care physician education. Although the treatment for preventing suicide is difficult, follow-up that includes pharmacotherapy, psychotherapy, or both may be useful. However, prevention methods cannot be restricted to the individual. Community, social, and policy interventions will also be essentia
Quantum Field Theory in the Large N Limit: a review
We review the solutions of O(N) and U(N) quantum field theories in the large
limit and as 1/N expansions, in the case of vector representations. Since
invariant composite fields have small fluctuations for large , the method
relies on constructing effective field theories for composite fields after
integration over the original degrees of freedom. We first solve a general
scalar U(\phib^2) field theory for large and discuss various
non-perturbative physical issues such as critical behaviour. We show how large
results can also be obtained from variational calculations.We illustrate
these ideas by showing that the large expansion allows to relate the
(\phib^2)^2 theory and the non-linear -model, models which are
renormalizable in different dimensions. Similarly, a relation between
and abelian Higgs models is exhibited. Large techniques also allow solving
self-interacting fermion models. A relation between the Gross--Neveu, a theory
with a four-fermi self-interaction, and a Yukawa-type theory renormalizable in
four dimensions then follows. We discuss dissipative dynamics, which is
relevant to the approach to equilibrium, and which in some formulation exhibits
quantum mechanics supersymmetry. This also serves as an introduction to the
study of the 3D supersymmetric quantum field theory. Large methods are
useful in problems that involve a crossover between different dimensions. We
thus briefly discuss finite size effects, finite temperature scalar and
supersymmetric field theories. We also use large methods to investigate the
weakly interacting Bose gas. The solution of the general scalar U(\phib^2)
field theory is then applied to other issues like tricritical behaviour and
double scaling limit.Comment: Review paper: 200 pages, 13 figure
Low-dose oral immunization with lyophilized tissue of herbicide-resistant lettuce expressing hepatitis B surface antigen for prototype plant-derived vaccine tablet formulation
Efficient immunization against hepatitis B virus (HBV) and other pathogens with plant-based oral vaccines requires appropriate plant expressors and the optimization of vaccine compositions and administration protocols. Previous immunization studies were mainly based on a combination of the injection of a small surface antigen of HBV (S-HBsAg) and the feeding with raw tissue containing the antigen, supplemented with an adjuvant, and coming from plants conferring resistance to kanamycin. The objective of this study was to develop a prototype oral vaccine formula suitable for human immunization. Herbicide-resistant lettuce was engineered, stably expressing through progeny generation micrograms of S-HBsAg per g of fresh weight and formed into virus-like particles (VLPs). Lyophilized tissue containing a relatively low, 100-ng VLP-assembled antigen dose, administered only orally to mice with a long, 60-day interval between prime and boost immunizations and without exogenous adjuvant, elicited mucosal and systemic humoral anti-HBs responses at the nominally protective level. Lyophilized tissue was converted into tablets, which preserved S-HBsAg content for at least one year of room temperature storage. The results of the study provide indications on immunization methodology using a durable, efficacious, and convenient plant-derived prototype oral vaccine against hepatitis B
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