182 research outputs found
The impact of pulsed electric field on the extraction of bioactive compounds from beetroot
Beetroot is a root vegetable rich in different bioactive components, such as vitamins, minerals, phenolics, carotenoids, nitrate, ascorbic acids, and betalains, that can have a positive effect on human health. The aim of this work was to study the influence of the pulsed electric field (PEF) at different electric field strengths (4.38 and 6.25 kV/cm), pulse number 10\u201330, and energy input 0\u201312.5 kJ/kg as a pretreatment method on the extraction of betalains from beetroot. The obtained results showed that the application of PEF pre-treatment significantly (p < 0.05) influenced the efficiency of extraction of bioactive compounds from beetroot. The highest increase in the content of betalain compounds in the red beet\u2019s extract (betanin by 329%, vulgaxanthin by 244%, compared to the control sample), was noted for 20 pulses of electric field at 4.38 kV/cm of strength. Treatment of the plant material with a PEF also resulted in an increase in the electrical conductivity compared to the non-treated sample due to the increase in cell membrane permeability, which was associated with leakage of substances able to conduct electricity, including mineral salts, into the intercellular space
A global reanalysis of nuclear parton distribution functions
We determine the nuclear modifications of parton distribution functions of
bound protons at scales GeV and momentum fractions
in a global analysis which utilizes nuclear hard process
data, sum rules and leading-order DGLAP scale evolution. The main improvements
over our earlier work {\em EKS98} are the automated minimization,
simplified and better controllable fit functions, and most importantly, the
possibility for error estimates. The resulting 16-parameter fit to the N=514
datapoints is good, . Within the error estimates
obtained, the old {\em EKS98} parametrization is found to be fully consistent
with the present analysis, with no essential difference in terms of
either. We also determine separate uncertainty bands for the nuclear gluon and
sea quark modifications in the large- region where they are not stringently
constrained by the available data. Comparison with other global analyses is
shown and uncertainties demonstrated. Finally, we show that RHIC-BRAHMS data
for inclusive hadron production in d+Au collisions lend support for a stronger
gluon shadowing at and also that fairly large changes in the gluon
modifications do not rapidly deteriorate the goodness of the overall fits, as
long as the initial gluon modifications in the region remain
small.Comment: 33 pages, 14 figure
Atomic Mass Dependence of Hadron Production in Deep Inelastic Scattering on Nuclei
Hadron production in lepton-nucleus deep inelastic scattering is studied in
an absorption model. In the proposed model, the early stage of hadronization in
the nuclear medium is dominated by prehadron formation and absorption,
controlled by flavor-dependent formation lengths and absorption cross sections.
Computations for hadron multiplicity ratios are presented and compared with the
HERMES experimental data for pions, kaons, protons and antiprotons. The
mass-number dependence of hadron attenuation is shown to be sensitive to the
underlying hadronization dynamics. Contrary to common expectations for
absorption models, a leading term proportional to A^{2/3} is found. Deviations
from the leading behavior arise at large mass-numbers and large hadron
fractional momenta.Comment: 30 pages, 10 figures, v2: minor changes (legend in figs 5 & 6 is
added), v3: additional explanations are added, v4: Version combines v3 and
the erratum hep-ph/050803
Estimate of the Collins fragmentation function in a chiral invariant approach
We predict the features of the Collins function, which describes the
fragmentation of a transversely polarized quark into an unpolarized hadron, by
modeling the fragmentation process at a low energy scale. We use the chiral
invariant approach of Manohar and Georgi, where constituent quarks and
Goldstone bosons are considered as effective degrees of freedom in the
non-perturbative regime of QCD. To test the approach we calculate the
unpolarized fragmentation function and the transverse momentum distribution of
a produced hadron, both of which are described reasonably well. In the case of
semi-inclusive deep-inelastic scattering, our estimate of the Collins function
in connection with the transversity distribution gives rise to a transverse
single spin asymmetry of the order of 10%, supporting the idea of measuring the
transversity distribution of the nucleon in this way. In the case of e+ e-
annihilation into two hadrons, our model predicts a Collins azimuthal asymmetry
of about 5%.Comment: 12 pages, 15 figures. Figs. 11-14 changed, minor changes in
discussion, few typos fixed and some references added. Final version to
appear in PR
Detection of blood clots using a whole stent as an active implantable biosensor
Many cardiovascular problems stem from blockages that form within the vasculature and often treatment includes fitting a stent through percutaneous coronary intervention. This offers a minimally invasive therapy but re-occlusion through restenosis or thrombosis formation often occurs post-deployment. Research is ongoing into the creation of smart stents that can detect the occurrence of further problems. In this study, it is shown that selectively metalizing a non-conductive stent can create a set of electrodes that are capable of detecting a build-up of material around the stent. The associated increase in electrical impedance across the electrodes is measured, testing the stent with blood clot to mimic thrombosis. It is shown that the device is capable of sensing different amounts of occlusion. The stent can reproducibly sense the presence of clot showing a 16% +/â3% increase in impedance which is sufficient to reliably detect the clot when surrounded by explanted aorta (one sample t-test, p = 0.009, n = 9). It is demonstrated that this approach can be extended beyond the 3D printed prototypes by showing that it can be applied to a commercially available stent and it is believed that it can be further utilized by other types of medical implants
Nuclear Attenuation of Fast Hadrons Produced in Charged-Current Neutrino and Antineutrino Interactions in Neon
The production of hadrons in charged-current (anti)neutrino interactions is
studied with the bubble chamber BEBC exposed ot the CERN (anti)neutrino
wide-band beam. Fast-hadron production in a neon target is found to be
attennuated as compared to that in a hydrogen target. This feature is discussed
within the theoretical models based on the idea of a hadron formation length.
The experimental results favour the `constituent' over the `yo-yo' length
concept, and suggest a quark cross-section in the order of 3mb.Comment: 14 pages + 7 figures, ps fil
Is there a difference between child self-ratings and parent proxy-ratings of the quality of life of children with a diagnosis of Attention Deficit Hyperactivity Disorder (ADHD)? A systematic review of the literature
There are contemporary indicators that parent proxy-ratings and child self-ratings of a childâs quality of life (QoL) are not interchangeable. This review examines dual informant studies to assess parentâchild agreement on the QoL of children with attention-deficit/hyperactivity disorder. A systematic search of four major databases (PsycINFO, MEDLINE, EMBASE and Cochrane databases) was completed, and related peer-reviewed journals were hand-searched. Studies which reported quantitative QoL ratings for matched parent and child dyads were screened in accordance with relevant inclusion and exclusion criteria. Key findings were extracted from thirteen relevant studies, which were rated for conformity to the recommendations of an adapted version of the STROBE statement guidelines for observational studies. In the majority of studies reviewed, children rated their QoL more highly than their parents. There was some evidence for greater agreement on the physical health domain than psychosocial domains
In Vivo, In Vitro, and In Silico Characterization of Peptoids as Antimicrobial Agents
Bacterial resistance to conventional antibiotics is a global threat that has spurred the development of antimicrobial peptides (AMPs) and their mimetics as novel anti-infective agents. While the bioavailability of AMPs is often reduced due to protease activity, the non-natural structure of AMP mimetics renders them robust to proteolytic degradation, thus offering a distinct advantage for their clinical application. We explore the therapeutic potential of N-substituted glycines, or peptoids, as AMP mimics using a multi-faceted approach that includes in silico, in vitro, and in vivo techniques. We report a new QSAR model that we developed based on 27 diverse peptoid sequences, which accurately correlates antimicrobial peptoid structure with antimicrobial activity. We have identified a number of peptoids that have potent, broad-spectrum in vitro activity against multi-drug resistant bacterial strains. Lastly, using a murine model of invasive S. aureus infection, we demonstrate that one of the best candidate peptoids at 4 mg/kg significantly reduces with a two-log order the bacterial counts compared with saline-treated controls. Taken together, our results demonstrate the promising therapeutic potential of peptoids as antimicrobial agents
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