2,812 research outputs found
Magnetic resonance spectroscopy reveals N-acetylaspartate reduction in hippocampus and cingulate cortex after fear conditioning
The fear conditioning in rodents provides a valuable translational tool to investigate the neural basis of learning and memory and potentially the neurobiology of post-traumatic stress disorder (PTSD). Neurobiological changes induced by fear conditioning have largely been examined ex vivo while progressive 'real-time' changes in vivo remain under-explored. Single voxel proton magnetic resonance spectroscopy (1H MRS) of the hippocampus, cingulate cortex and thalamus of adult male C57BL/6N mice (N=12) was performed at 1 day before, 1 day and 1 week after, fear conditioning training using a 7T scanner. N-acetylaspartate (NAA), a marker for neuronal integrity and viability, significantly decreased in the hippocampus at 1 day and 1 week post-conditioning. Significant NAA reduction was also observed in the cingulate cortex at 1 day post-conditioning. These findings of hippocampal NAA decrease indicate reduced neuronal dysfunction and/or neuronal integrity, contributing to the trauma-related PTSD-like symptoms. The neurochemical changes characterized by 1H MRS can shed light on the biochemical mechanisms of learning and memory. Moreover, such information can potentially facilitate prompt intervention for patients with psychiatric disorders. © 2012 Elsevier Ireland Ltd.postprin
MEMRI study neonatal hypoxic-ischemic injury in the late stage
Session 16: Manganese Enhanced MRI: Methods & Applications - Oral presentationIn this study, in vivo MEMRI was employed to investigate the hypoxic-ischemic injury in the late phase. Mn2+ induced signal changes were examined using SPM coregistration and ROI analysis. T1WIs SI increase was detected in the perilesional region 24 hours after Mn2+ administration and it colocalized with the increase in glial cell density in GFAP staining, demonstrating the existence of reactive gliosis in the late phase after H-I injury.published_or_final_versionThe 17th Scientific Meeting & Exhibition of the International Society of Magnetic Resonance in Medicine (ISMRM), Honolulu, HI., 18-24 April 2009. In Proceedings of ISMRM 17th Scientific Meeting & Exhibition, 2009, p. 15
Hierarchical CO2-protective shell for highly efficient oxygen reduction reaction
The widespread application of intermediate-temperature solid oxide fuel cells is mainly being hurdled by the cathode's low efficiency on oxygen reduction reaction and poor resistance to carbon dioxide impurity. Here we report the fabrication of a hierarchical shell-covered porous cathode through infiltration followed by microwave plasma treatment. The hierarchical shell consists of a dense thin-film substrate with cones on the top of the substrate, leading to a three-dimensional (3D) heterostructured electrode. The shell allows the cathode working stably in CO2-containing air, and significantly improving the cathode's oxygen reduction reactivity with an area specific resistance of ∼0.13 Ωcm2 at 575°C. The method is also suitable for fabricating functional shell on the irregularly shaped substrate in various applications
Correlation in states of two identical particles
We identify the correlation in a state of two identical particles as the
residual information beyond what is already contained in the 1-particle reduced
density matrix, and propose a correlation measure based on the maximum entropy
principle. We obtain the analytical results of the correlation measure, which
make it computable for arbitrary two-particle states. We also show that the
degrees of correlation in the same two-particle states with different particle
types will decrease in the following order: bosons, fermions, and
distinguishable particles.Comment: 3.6 page
Transgenic plant-derived siRNAs can suppress propagation of influenza virus in mammalian cells
As an example of the cost-effective large-scale generation of small-interfering RNA (siRNAs), we have created transgenic tobacco plants that produce siRNAs targeted to the mRNA of the non-structural protein NS1 from the influenza A virus subtype H1N1. We have investigated if these siRNAs, specifically targeted to the 5 ′-portion of the NS1 transcripts (5mNS1), would suppress viral propagation in mammalian cells. Agroinfiltration of transgenic tobacco with an Agrobacterium strain harboring a 5mNS1-expressing binary vector caused a reduction in 5mNS1 transcripts in the siRNA-accumulating transgenic plants. Further, H1N1 infection of siRNA-transfected mammalian cells resulted in significant suppression of viral replication. These results demonstrate that plant-derived siRNAs can inhibit viral propagation through RNA interference and could potentially be applied in control of viral-borne diseases. © 2004 Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.postprin
Analysing multiparticle quantum states
The analysis of multiparticle quantum states is a central problem in quantum
information processing. This task poses several challenges for experimenters
and theoreticians. We give an overview over current problems and possible
solutions concerning systematic errors of quantum devices, the reconstruction
of quantum states, and the analysis of correlations and complexity in
multiparticle density matrices.Comment: 20 pages, 4 figures, prepared for proceedings of the "Quantum
[Un]speakables II" conference (Vienna, 2014
Quantum Computing with Very Noisy Devices
In theory, quantum computers can efficiently simulate quantum physics, factor
large numbers and estimate integrals, thus solving otherwise intractable
computational problems. In practice, quantum computers must operate with noisy
devices called ``gates'' that tend to destroy the fragile quantum states needed
for computation. The goal of fault-tolerant quantum computing is to compute
accurately even when gates have a high probability of error each time they are
used. Here we give evidence that accurate quantum computing is possible with
error probabilities above 3% per gate, which is significantly higher than what
was previously thought possible. However, the resources required for computing
at such high error probabilities are excessive. Fortunately, they decrease
rapidly with decreasing error probabilities. If we had quantum resources
comparable to the considerable resources available in today's digital
computers, we could implement non-trivial quantum computations at error
probabilities as high as 1% per gate.Comment: 47 page
Who will use pre-exposure prophylaxis (PrEP) and why?: Understanding PrEP awareness and acceptability amongst men who have sex with men in the UK – a mixed methods study
Background:
Recent clinical trials suggest that pre-exposure prophylaxis (PrEP) may reduce HIV transmission by up to 86% for men who have sex with men (MSM), whilst relatively high levels of PrEP acceptability have been reported to date. This study examines PrEP awareness amongst sub-groups of MSM communities and acceptability amongst MSM in a low prevalence region (Scotland, UK), using a mixed methods design.
Methods:
Quantitative surveys of n = 690 MSM recruited online via social and sociosexual media were analysed using descriptive statistics and multivariate logistic regression. In addition, n = 10 in-depth qualitative interviews with MSM were analysed thematically.
Results:
Under one third (29.7%) of MSM had heard of PrEP, with awareness related to living in large cities, degree level education, commercial gay scene use and reporting an HIV test in the last year. Just under half of participants (47.8%) were likely to use PrEP if it were available but there was no relationship between PrEP acceptability and previous PrEP awareness. Younger men (18–25 years) and those who report higher risk UAI were significantly more likely to say they would use PrEP. Qualitative data described specific PrEP scenarios, illustrating how risk, patterns of sexual practice and social relationships could affect motivation for and nature of PrEP use.
Conclusion:
These findings suggest substantial interest PrEP amongst MSM reporting HIV risk behaviours in Scotland. Given the Proud results, there is a strong case to investigate PrEP implementation within the UK. However, it appears that disparities in awareness have already emerged along traditional indicators of inequality. Our research identifies the need for comprehensive support when PrEP is introduced, including a key online component, to ensure equity of awareness across diverse MSM communities (e.g. by geography, education, gay scene use and HIV proximity), as well as to responding to the diverse informational and sexual health needs of all MSM communities
Monitoring iron chelation effect in hearts of thalassaemia patients with improved sensitivity using reduced transverse relaxation rate (RR2)
Posters - Myocardial Viability: Human Models: No. 3660Accurate MRI characterization of myocardial iron is needed to improve the diagnosis and management of thalassaemia patients with transfusional iron overload. This study aimed to demonstrate that a new transverse relaxation index, the reduced R2 (RR2) that is estimated from non-monoexponential multi-echo CPMG signal decay and sensitive to ferritin iron, could detect the myocardial iron changes immediately following 1-week iron chelation suspension in thalassaemia patients at 3T.postprin
Relations among neutrino observables in the light of a large theta_13 angle
The recent T2K and MINOS indications for a "large" theta_13 neutrino mixing
angle can be accommodated in principle by an infinite number of Yukawa flavour
structures in the seesaw model. Without considering any explicit flavour
symmetry, there is an instructive exercise one can do: to determine the
simplest flavour structures which can account for the data with a minimum
number of parameters, simply assuming these parameters to be uncorrelated. This
approach points towards a limited number of simple structures which show the
minimum complexity a neutrino mass model must generally involve to account for
the data. These basic structures essentially lead to only 4 relations between
the neutrino observables. We emphasize that 2 of these relations, |sin
theta_13|=(tan theta_23/cos delta)*(1-tan theta_12)/(1+tan theta_12) and |sin
theta_13| = sin theta_12 R^1/4, with R= Delta m^2_21/Delta m^2_32, have several
distinctive properties. First, they hold not only with a minimum number of
parameters, but also for complete classes of more general models. Second, any
value of theta_13 within the T2K and MINOS ranges can be obtained from these
relations by taking into account small perturbations. Third, they turn out to
be the pivot relations of models with approximate conservation of lepton
number, which allow the seesaw interactions to induce observable flavour
violating processes, such as mu -> e gamma and tau -> mu gamma. Finally, in
specific cases of this kind, these structures have the rather unique property
to allow a full reconstruction of the seesaw Lagrangian from low energy data.Comment: 13 pages, 3 figure
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