32,663 research outputs found
Berberine for prevention of dementia associated with diabetes and its comorbidities: A systematic review
Background
A growing number of epidemiological studies indicate that metabolic syndrome (MetS) and its associated features play a key role in the development of certain degenerative brain disorders, including Alzheimer’s disease and vascular dementia. Produced by several different medicinal plants, berberine is a bioactive alkaloid with a wide range of pharmacological effects, including antidiabetic effects. However, it is not clear whether berberine could prevent the development of dementia in association with diabetes.
Objective
To give an overview of the therapeutic potential of berberine as a treatment for dementia associated with diabetes.
Search strategy
Database searches A and B were conducted using PubMed and ScienceDirect. In search A, studies on berberine’s antidementia activities were identified using “berberine” and “dementia” as search terms. In search B, recent studies on berberine’s effects on diabetes were surveyed using “berberine” and “diabetes” as search terms.
Inclusion criteria
Clinical and preclinical studies that investigated berberine’s effects associated with MetS and cognitive dysfunction were included.
Data extraction and analysis
Data from studies were extracted by one author, and checked by a second; quality assessments were performed independently by two authors.
Results
In search A, 61 articles were identified, and 22 original research articles were selected. In search B, 458 articles were identified, of which 101 were deemed relevant and selected. Three duplicates were removed, and a total of 120 articles were reviewed for this study. The results demonstrate that berberine exerts beneficial effects directly in the brain: enhancing cholinergic neurotransmission, improving cerebral blood flow, protecting neurons from inflammation, limiting hyperphosphorylation of tau and facilitating β-amyloid peptide clearance. In addition, evidence is growing that berberine is effective against diabetes and associated disorders, such as atherosclerosis, cardiomyopathy, hypertension, hepatic steatosis, diabetic nephropathy, gut dysbiosis, retinopathy and neuropathy, suggesting indirect benefits for the prevention of dementia.
Conclusion
Berberine could impede the development of dementia via multiple mechanisms: preventing brain damages and enhancing cognition directly in the brain, and indirectly through alleviating risk factors such as metabolic dysfunction, and cardiovascular, kidney and liver diseases. This study provided evidence to support the value of berberine in the prevention of dementia associated with MetS
Not throwing out the baby with the bathwater: Bell's condition of local causality mathematically 'sharp and clean'
The starting point of the present paper is Bell's notion of local causality
and his own sharpening of it so as to provide for mathematical formalisation.
Starting with Norsen's (2007, 2009) analysis of this formalisation, it is
subjected to a critique that reveals two crucial aspects that have so far not
been properly taken into account. These are (i) the correct understanding of
the notions of sufficiency, completeness and redundancy involved; and (ii) the
fact that the apparatus settings and measurement outcomes have very different
theoretical roles in the candidate theories under study. Both aspects are not
adequately incorporated in the standard formalisation, and we will therefore do
so. The upshot of our analysis is a more detailed, sharp and clean mathematical
expression of the condition of local causality. A preliminary analysis of the
repercussions of our proposal shows that it is able to locate exactly where and
how the notions of locality and causality are involved in formalising Bell's
condition of local causality.Comment: 14 pages. To be published in PSE volume "Explanation, Prediction, and
Confirmation", edited by Dieks, et a
A new test of conservation laws and Lorentz invariance in relativistic gravity
General relativity predicts that energy and momentum conservation laws hold
and that preferred frames do not exist. The parametrised post-Newtonian
formalism (PPN) phenomenologically quantifies possible deviations from general
relativity. The PPN parameter alpha_3 (which identically vanishes in general
relativity) plays a dual role in that it is associated both with a violation of
the momentum conservation law, and with the existence of a preferred frame. By
considering the effects of alpha_3 neq 0 in certain binary pulsar systems, it
is shown that alpha_3 < 2.2 x 10^-20 (90% CL). This limit improves on previous
results by several orders of magnitude, and shows that pulsar tests of alpha_3
rank (together with Hughes-Drever-type tests of local Lorentz invariance) among
the most precise null experiments of physics.Comment: Submitted to Classical Quantum Gravity, LaTeX, requires ioplppt.sty,
no figure
Toward a Deterministic Model of Planetary Formation IV: Effects of Type-I Migration
In a further development of a deterministic planet-formation model (Ida & Lin
2004), we consider the effect of type-I migration of protoplanetary embryos due
to their tidal interaction with their nascent disks. During the early embedded
phase of protostellar disks, although embryos rapidly emerge in regions
interior to the ice line, uninhibited type-I migration leads to their efficient
self-clearing. But, embryos continue to form from residual planetesimals at
increasingly large radii, repeatedly migrate inward, and provide a main channel
of heavy element accretion onto their host stars. During the advanced stages of
disk evolution (a few Myr), the gas surface density declines to values
comparable to or smaller than that of the minimum mass nebula model and type-I
migration is no longer an effective disruption mechanism for mars-mass embryos.
Over wide ranges of initial disk surface densities and type-I migration
efficiency, the surviving population of embryos interior to the ice line has a
total mass several times that of the Earth. With this reservoir, there is an
adequate inventory of residual embryos to subsequently assemble into rocky
planets similar to those around the Sun. But, the onset of efficient gas
accretion requires the emergence and retention of cores, more massive than a
few M_earth, prior to the severe depletion of the disk gas. The formation
probability of gas giant planets and hence the predicted mass and semimajor
axis distributions of extrasolar gas giants are sensitively determined by the
strength of type-I migration. We suggest that the observed fraction of
solar-type stars with gas giant planets can be reproduced only if the actual
type-I migration time scale is an order of magnitude longer than that deduced
from linear theories.Comment: 32 pages, 8 figures, 1 table, accepted for publication in Ap
Electromagnetic Magic: The Relativistically Rotating Disk
A closed form analytic solution is found for the electromagnetic field of the
charged uniformly rotating conducting disk for all values of the tip speed
up to . For it becomes the Magic field of the Kerr-Newman black hole
with set to zero.
The field energy, field angular momentum and gyromagnetic ratio are
calculated and compared with those of the electron.
A new mathematical expression that sums products of 3 Legendre functions each
of a different argument, is demonstrated.Comment: 10 pages, one figur
Ensemble inequivalence, bicritical points and azeotropy for generalized Fofonoff flows
We present a theoretical description for the equilibrium states of a large
class of models of two-dimensional and geophysical flows, in arbitrary domains.
We account for the existence of ensemble inequivalence and negative specific
heat in those models, for the first time using explicit computations. We give
exact theoretical computation of a criteria to determine phase transition
location and type. Strikingly, this criteria does not depend on the model, but
only on the domain geometry. We report the first example of bicritical points
and second order azeotropy in the context of systems with long range
interactions.Comment: 4 pages, submitted to Phys. Rev. Let
Non-local two-photon correlations using interferometers physically separated by 35 meters
An experimental demonstration of quantum correlations is presented. Energy
and time entangled photons at wavelengths of 704 and 1310 nm are produced by
parametric downconversion in KNbO3 and are sent through optical fibers into a
bulk-optical (704 nm) and an all-fiber Michelson-interferometer (1310 nm),
respectively. The two interferometers are located 35 meters aside from one
another. Using Faraday-mirrors in the fiber-interferometer, all birefringence
effects in the fibers are automatically compensated. We obtained two-photon
fringe visibilities of up to 95 % from which one can project a violation of
Bell's inequality by 8 standard deviations. The good performance and the
auto-aligning feature of Faraday-mirror interferometers show their potential
for a future test of Bell's inequalities in order to examine
quantum-correlations over long distances.Comment: 9 pages including 3 postscript figures, to be published in Europhys.
Let
Atom-photon, atom-atom and photon-photon entanglement preparation via fractional adiabatic passage
We propose a relatively robust scheme to generate maximally entangled states
of (i) an atom and a cavity photon, (ii) two atoms in their ground states, and
(iii) two photons in two spatially separate high-Q cavities. It is based on the
interaction via fractional adiabatic passage of a three-level atom traveling
through a cavity mode and a laser beam. The presence of optical phases is
emphasized.Comment: 6 pages, 7 figures. We have changed the title, the abstract and the
text. The references have been updated. (Accepted by Phys. Rev. A
A Bell-type test of energy-time entangled qutrits
We have performed a Bell-type test for energy-time entangled qutrits. A
method of inferring the Bell violation in terms of an associated interference
visibility is derived. Using this scheme we obtained a Bell value of , representing a violation of above the limit for local
variables. The scheme has been developed for use at telecom wavelengths and
using proven long distance quantum communication architecture to optimize the
utility of this high dimensional entanglement resource.Comment: replaced lost acknowledement
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