5,734 research outputs found
Medicinal Plants of Chile: Evaluation of their Anti-Trypanosoma cruzi Activity
San Martin, J (San Martin, Jose). Univ Talca, Inst Biol Vegetal & Biotecnol, Talca, ChileThe extracts of several plants of Central Chile exhibited anti-Trypanosoma cruzi trypomastigotes activity. Most active extracts were those obtained from Podanthus ovatifolius, Berberis microphylla, Kageneckia oblonga, and Drimys winteri. The active extract of Drimys winteri (IC50 51.2 mu g/mL) was purified and three drimane sesquiterpenes were obtained: polygodial, drimenol, and isodrimenin. Isodrimenin and drimenol were found to be active against the trypomastigote form of T cruzi with IC50 values of 27.9 and 25.1 mu M, respectivel
Tailored Graphenic Structures Directly Grown on Titanium Oxide Boost the Interfacial Charge Transfer
The successful application of titanium oxide-graphene hybrids in the fields
of photocatalysis, photovoltaics and photodetection strongly depends on the
interfacial contact between both materials. The need to provide a good coupling
between the enabling conductor and the photoactive phase prompted us to
directly grow conducting graphenic structures on TiO2 crystals. We here report
on the direct synthesis of tailored graphenic structures by using Plasma
Assisted Chemical Vapour Deposition that present a clean junction with the
prototypical titanium oxide (110) surface. Chemical analysis of the interface
indicates chemical bonding between both materials. Photocurrent measurements
under UV light illumination manifest that the charge transfer across the
interface is efficient. Moreover, the influence of the synthesis atmosphere,
gas precursor (C2H2) and diluents (Ar, O2), on the interface and on the
structure of the as-grown graphenic material is assessed. The inclusion of O2
promotes vertical growth of partially oxidized carbon nanodots/rods with
controllable height and density. The deposition with Ar results in continuous
graphenic films with low resistivity (6.8x10-6 ohm x m). The synthesis
protocols developed here are suitable to produce tailored carbon-semiconductor
structures on a variety of practical substrates as thin films, pillars or
nanoparticles.Comment: 24 pages, 8 figures, original research pape
Sequential Anisotropic Multichannel Wiener Filtering with Rician Bias Correction Applied to 3D Regularization of DWI Data
It has been shown that the tensor calculation is very sensitive to the presence of noise in the acquired images, yielding to very low-quality Diffusion Tensor Images (DTI) data. Recent investigations have shown that the noise present in the Diffusion Weighted Images (DWI) causes bias effects on the DTI data which cannot be corrected if the noise characteristic is not taken into account. One possible solution is to increase the minimum number of acquired measurements (which is 7) to several tens (or even several hundreds). This has the disadvantage of increasing the acquisition time by one (or two) orders of magnitude, making the process inconvenient for a clinical setting. We here proposed a turn-around procedure for which the number of acquisitions is maintained but, the DWI data are filtered prior to determining the DTI. We show a significant reduction on the DTI bias by means of a simple and fast procedure which is based on linear filtering; well- known drawbacks of such filters are circumvented by means of anisotropic neighborhoods and sequential application of the filter itself. Information of the first order probability density function of the raw data, namely, the Rice distribution, is also included. Results are shown both for synthetic and real datasets. Some error measurements are measured in the synthetic experiments, showing how the proposed scheme is able to reduce them. It is worth noting a 50% increase in the linear component for real DTI data, meaning that the bias in the DTI is considerably reduced. A novel fiber smoothness measure is defined to evaluate the resulting tractography for real DWI data. Our findings show that after filtering fibers are considerably smoother on the average. Execution times are very low as compared to other reported approaches which allows for a real-time implementation
From early contraction to post-folding fluid evolution in the frontal part of the boixols thrust sheet (southern pyrenees) as revealed by the texture and geochemistry of calcite cements
Structural, petrological and geochemical (δ13C, δ18O, clumped isotopes, 87Sr/86Sr and ICP-MS) analyses of fracture-related calcite cements and host rocks are used to establish a fluid-flow evolution model for the frontal part of the Bóixols thrust sheet (Southern Pyrenees). Five fracture events associated with the growth of the thrust-related Bóixols anticline and Coll de Nargó syncline during the Alpine orogeny are distinguished. These fractures were cemented with four generations of calcite cements, revealing that such structures allowed the migration of different marine and meteoric fluids through time. During the early contraction stage, Lower Cretaceous seawater circulated and precipitated calcite cement Cc1, whereas during the main folding stage, the system opened to meteoric waters, which mixed with the connate seawater and precipitated calcite cement Cc2. Afterwards, during the post-folding stages, connate evaporated marine fluids circulated through newly formed NW-SE and NE-SW conjugate fractures and later through strike-slip faults and precipitated calcite cements Cc3 and Cc4. The overall paragenetic sequence reveals the progressive dewatering of Cretaceous marine host sediments during progressive burial, deformation and fold tightening and the input of meteoric waters only during the main folding stage. This study illustrates the changes of fracture systems and the associated fluid-flow regimes during the evolution of fault-associated folds during orogenic growth
Intracellular interferons in fish : a unique means to combat viral infection
Peer reviewedPublisher PD
Constrained Supersymmetric Flipped SU(5) GUT Phenomenology
We explore the phenomenology of the minimal supersymmetric flipped SU(5) GUT
model (CFSU(5)), whose soft supersymmetry-breaking (SSB) mass parameters are
constrained to be universal at some input scale, , above the GUT scale,
. We analyze the parameter space of CFSU(5) assuming that the lightest
supersymmetric particle (LSP) provides the cosmological cold dark matter,
paying careful attention to the matching of parameters at the GUT scale. We
first display some specific examples of the evolutions of the SSB parameters
that exhibit some generic features. Specifically, we note that the relationship
between the masses of the lightest neutralino and the lighter stau is sensitive
to , as is the relationship between the neutralino mass and the masses
of the heavier Higgs bosons. For these reasons, prominent features in generic
planes such as coannihilation strips and rapid-annihilation
funnels are also sensitive to , as we illustrate for several cases with
tan(beta)=10 and 55. However, these features do not necessarily disappear at
large , unlike the case in the minimal conventional SU(5) GUT. Our
results are relatively insensitive to neutrino masses.Comment: 23 pages, 8 figures; (v2) added explanations and corrected typos,
version to appear in EPJ
Blood-brain barrier failure as a core mechanism in cerebral small vessel disease and dementia: evidence from a cohort study
Introduction: Small vessel disease (SVD) is a common contributor to dementia. Subtle blood-brain
barrier (BBB) leakage may be important in SVD-induced brain damage.
Methods: We assessed imaging, clinical variables, and cognition in patients with mild (i.e., nondisabling)
ischemic lacunar or cortical stroke. We analyzed BBB leakage, interstitial fluid, and white
matter integrity using multimodal tissue-specific spatial analysis around white matter hyperintensities
(WMH). We assessed predictors of 1 year cognition, recurrent stroke, and dependency.
Results: In 201 patients, median age 67 (range 34–97), BBB leakage, and interstitial fluid were
higher in WMH than normal-appearing white matter; leakage in normal-appearing white matter
increased with proximity to WMH (P , .0001), with WMH severity (P 5 .033), age (P 5 .03),
and hypertension (P , .0001). BBB leakage in WMH predicted declining cognition at 1 year.
Discussion: BBB leakage increases in normal-appearing white matter with WMH and predicts worsening
cognition. Interventions to reduce BBB leakage may prevent SVD-associated dementia
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