2,344 research outputs found
Effects of Saccharomyces boulardii on antibiotic induced orocecal transit in rats
Clarithromycin is an antibiotic widely used for Helicobacter pylori (H. pylori) eradication and together with amoxicillin and proton pump inhibitors they constitute the first line triple treatment regimen against H. pylori. Diarrhoea is one of the major drawbacks during H. pylori eradication and is majorly attributed to clarithromycin, while Saccharomyces boulardii is a probiotic and is shown to be effective in the treatment of antibiotic associated diarrhoea. We aimed to evaluate the effect of clarithromycin on orocecal transit in rats and to identify whether the supplementation with S. boulardii has a role on orocecal transit index. Adult rats of both sexes were divided into two groups to determine immediate or chronic effects of S. boulardii and clarithromycin on orocecal transit. The first group was given single dose of the test drug, while the second group received the test drugs for one week through orogastric intubation. Both groups were randomly distributed into four subgroups; the placebo group (group A), the S. boulardii group (group B), the clarithromycin group (group C), and the co-administration that is clarithromycin plus S. boulardii group (group D). Rats were given 20 mg kg−1 clarithromycin and 500 mg kg−1S. boulardii. We did not find any difference among the subgroups in group 1, where only single dose of the test drugs was administered. In chronic administration group, that is group 2, significant differences among the subgroups were observed (P=0.004). Post-hoc comparisons of orocecal transit index between group “2A and 2C” and “2C and 2D” were significantly different (P=0.013 and P=0.005, respectively). Our results show that long term clarithromycin administration leads to rapid orocecal transit index and S. boulardii supplementation to clarithromycin can abolish this adverse effect in rats. Those findings suggest the beneficial use of S. boulardii in H. pylori eradication regimens
Quantum Non-Demolition Bell State Measurement and N-party GHZ State Preparation in Quantum Dot
By exploiting the fermionic qubit parity measurement, we present a scheme to
realize quantum non-demolition (QND) measurement of Bell-states and generate
n-party GHZ state in quantum dot. Compared with the original protocol, the
required electron transfer before and after parity measurement can be
nonadiabatic, which may speed up the operation speed and make the omitting of
spin-orbit interaction more reasonable. This may help us to construct CNOT gate
without highly precise control of coupling as the way of D. Gottesman and I. L.
Chuang.Comment: some modification to introduction and some details are adde
Numerical observation of non-axisymmetric vesicles in fluid membranes
By means of Surface Evolver (Exp. Math,1,141 1992), a software package of
brute-force energy minimization over a triangulated surface developed by the
geometry center of University of Minnesota, we have numerically searched the
non-axisymmetric shapes under the Helfrich spontaneous curvature (SC) energy
model. We show for the first time there are abundant mechanically stable
non-axisymmetric vesicles in SC model, including regular ones with intrinsic
geometric symmetry and complex irregular ones. We report in this paper several
interesting shapes including a corniculate shape with six corns, a
quadri-concave shape, a shape resembling sickle cells, and a shape resembling
acanthocytes. As far as we know, these shapes have not been theoretically
obtained by any curvature model before. In addition, the role of the
spontaneous curvature in the formation of irregular crenated vesicles has been
studied. The results shows a positive spontaneous curvature may be a necessary
condition to keep an irregular crenated shape being mechanically stable.Comment: RevTex, 14 pages. A hard copy of 8 figures is available on reques
Self-repair ability of evolved self-assembling systems in cellular automata
Self-repairing systems are those that are able to reconfigure themselves following disruptions to bring them back into a defined normal state. In this paper we explore the self-repair ability of some cellular automata-like systems, which differ from classical cellular automata by the introduction of a local diffusion process inspired by chemical signalling processes in biological development. The update rules in these systems are evolved using genetic programming to self-assemble towards a target pattern. In particular, we demonstrate that once the update rules have been evolved for self-assembly, many of those update rules also provide a self-repair ability without any additional evolutionary process aimed specifically at self-repair
Squeezing and entanglement in continous variable systems
Based on total variance of a pair of Einstein-Podolsky-Rosen (EPR) type
operators, the generalized EPR entangled states in continuous variable systems
are defined. We show that such entangled states must correspond with two-mode
squeezing states whether these states are Gaussian or not and whether they are
pure or not. With help of the relation between the total variance and the
entanglement, the degree of such entanglement is also defined. Through
analyzing some specific cases, we see that this method is very convenient and
easy in practical application. In addition, an entangled state with no
squeezing is studied, which reveals that there certainly exist something
unknown about entanglement in continuous variable systems.Comment: 5 page
Experimental Test of Bell inequalities with Six-Qubit Graph States
We report on the experimental realization of two different Bell inequality
tests based on six-qubit linear-type and Y-shape graph states. For each of
these states, the Bell inequalities tested are optimal in the sense that they
provide the maximum violation among all Bell inequalities with stabilizing
observables and possess the maximum resistance to noise.Comment: 4 pages, 2 figure
Large Deformation Diffeomorphic Metric Mapping Registration of Reconstructed 3D Histological Section Images and in vivo MR Images
Our current understanding of neuroanatomical abnormalities in neuropsychiatric diseases is based largely on magnetic resonance imaging (MRI) and post mortem histological analyses of the brain. Further advances in elucidating altered brain structure in these human conditions might emerge from combining MRI and histological methods. We propose a multistage method for registering 3D volumes reconstructed from histological sections to corresponding in vivo MRI volumes from the same subjects: (1) manual segmentation of white matter (WM), gray matter (GM) and cerebrospinal fluid (CSF) compartments in histological sections, (2) alignment of consecutive histological sections using 2D rigid transformation to construct a 3D histological image volume from the aligned sections, (3) registration of reconstructed 3D histological volumes to the corresponding 3D MRI volumes using 3D affine transformation, (4) intensity normalization of images via histogram matching, and (5) registration of the volumes via intensity based large deformation diffeomorphic metric (LDDMM) image matching algorithm. Here we demonstrate the utility of our method in the transfer of cytoarchitectonic information from histological sections to identify regions of interest in MRI scans of nine adult macaque brains for morphometric analyses. LDDMM improved the accuracy of the registration via decreased distances between GM/CSF surfaces after LDDMM (0.39 ± 0.13 mm) compared to distances after affine registration (0.76 ± 0.41 mm). Similarly, WM/GM distances decreased to 0.28 ± 0.16 mm after LDDMM compared to 0.54 ± 0.39 mm after affine registration. The multistage registration method may find broad application for mapping histologically based information, for example, receptor distributions, gene expression, onto MRI volumes
Measurement Induced Quantum Coherence Recovery
We show that measurement can recover the quantum coherence of a qubit in a
non-Markovian environment. The experimental demonstration in an optical system
is provided by comparing the visibilities (and fidelities) of the final states
with and without measurement. This method can be extended to other two-level
quantum systems and entangled states in a non-Markovian evolution environment.
It may also be used to implement other quantum information processing.Comment: 9 pages, 5 figure
Causal Set Dynamics: A Toy Model
We construct a quantum measure on the power set of non-cyclic oriented graphs
of N points, drawing inspiration from 1-dimensional directed percolation.
Quantum interference patterns lead to properties which do not appear to have
any analogue in classical percolation. Most notably, instead of the single
phase transition of classical percolation, the quantum model displays two
distinct crossover points. Between these two points, spacetime questions such
as "does the network percolate" have no definite or probabilistic answer.Comment: 28 pages incl. 5 figure
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