38 research outputs found
Pickering emulsion stabilized by cashew gum- poly-l-lactide copolymer nanoparticles: Synthesis, characterization and amphotericin B encapsulation
In this work, we provide proof-of-concept of formation, physical characteristics and potential use as a drug delivery formulation of Pickering emulsions (PE) obtained by a novel method that combines nanoprecipitation with subsequent spontaneous emulsification process. To this end, pre-formed ultra-small (d.∼10 nm) nanoprecipitated nanoparticles of hydrophobic derivatives of cashew tree gum grafted with polylactide (CGPLAP), were conceived to stabilize Pickering emulsions obtained by spontaneous emulsification. These were also loaded with Amphotericin B (AmB), a drug of low oral bioavailability used in the therapy of neglected diseases such as leishmaniasis. The graft reaction was performed in two CG/PLA molar ratio conditions (1:1 and 1:10). Emulsions were prepared by adding the organic phase (Miglyol 812®) in the aqueous phase (nanoprecipitated CGPLAP), resulting the immediate emulsion formation. The isolation by centrifugation does not destabilize or separate the nanoparticles from oil droplets of the PE emulsion. Emulsions with CGPLAP 1:1 presented unimodal distributions at different CGPLA concentration, lower values in size and PDI and the best stability over time. The AmB was incorporated in the emulsions with a process efficiency of 21-47%, as determined by UV-vis. AmB in CGPLAP emulsions is in less aggregated state than observed in commercial AmB formulation
Observation of two new baryon resonances
Two structures are observed close to the kinematic threshold in the mass spectrum in a sample of proton-proton collision data, corresponding
to an integrated luminosity of 3.0 fb recorded by the LHCb experiment.
In the quark model, two baryonic resonances with quark content are
expected in this mass region: the spin-parity and
states, denoted and .
Interpreting the structures as these resonances, we measure the mass
differences and the width of the heavier state to be
MeV,
MeV,
MeV, where the first and second
uncertainties are statistical and systematic, respectively. The width of the
lighter state is consistent with zero, and we place an upper limit of
MeV at 95% confidence level. Relative
production rates of these states are also reported.Comment: 17 pages, 2 figure
Precision measurement of violation in decays
The time-dependent asymmetry in decays is
measured using collision data, corresponding to an integrated luminosity
of fb, collected with the LHCb detector at centre-of-mass energies
of and TeV. In a sample of 96 000 decays, the
-violating phase is measured, as well as the decay widths
and of the light and heavy mass eigenstates of the
system. The values obtained are rad, ps, andps, where the first uncertainty is
statistical and the second systematic. These are the most precise single
measurements of those quantities to date. A combined analysis with decays gives rad. All
measurements are in agreement with the Standard Model predictions. For the
first time the phase is measured independently for each polarisation
state of the system and shows no evidence for polarisation
dependence.Comment: 6 figure
Approaches in biotechnological applications of natural polymers
Natural polymers, such as gums and mucilage, are biocompatible, cheap, easily available and non-toxic materials of native origin. These polymers are increasingly preferred over synthetic materials for industrial applications due to their intrinsic properties, as well as they are considered alternative sources of raw materials since they present characteristics of sustainability, biodegradability and biosafety. As definition, gums and mucilages are polysaccharides or complex carbohydrates consisting of one or more monosaccharides or their derivatives linked in bewildering variety of linkages and structures. Natural gums are considered polysaccharides naturally occurring in varieties of plant seeds and exudates, tree or shrub exudates, seaweed extracts, fungi, bacteria, and animal sources. Water-soluble gums, also known as hydrocolloids, are considered exudates and are pathological products; therefore, they do not form a part of cell wall. On the other hand, mucilages are part of cell and physiological products. It is important to highlight that gums represent the largest amounts of polymer materials derived from plants. Gums have enormously large and broad applications in both food and non-food industries, being commonly used as thickening, binding, emulsifying, suspending, stabilizing agents and matrices for drug release in pharmaceutical and cosmetic industries. In the food industry, their gelling properties and the ability to mold edible films and coatings are extensively studied. The use of gums depends on the intrinsic properties that they provide, often at costs below those of synthetic polymers. For upgrading the value of gums, they are being processed into various forms, including the most recent nanomaterials, for various biotechnological applications. Thus, the main natural polymers including galactomannans, cellulose, chitin, agar, carrageenan, alginate, cashew gum, pectin and starch, in addition to the current researches about them are reviewed in this article.. }To the Conselho Nacional de Desenvolvimento Cientfíico e Tecnológico (CNPq) for fellowships (LCBBC and MGCC) and the Coordenação de Aperfeiçoamento de Pessoal de Nvíel Superior (CAPES) (PBSA). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and COMPETE 2020 (POCI-01-0145-FEDER-006684) (JAT)
Measurement of the inelastic pp cross-section at a centre-of-mass energy of √s = 7 TeV
The cross-section for inelastic proton-proton collisions, with at least one
prompt long-lived charged particle of transverse momentum pT > 0.2GeV/c in the pseudorapidity
range 2.0 > η > 4.5, is measured by the LHCb experiment at a centre-ofmass
energy of √
s = 7 TeV. The cross-section in this kinematic range is determined to
be σ
acc
inel = 55.0 ± 2.4 mb with an experimental uncertainty that is dominated by systematic
contributions. Extrapolation to the full phase space, using Pythia 6, yields
σinel = 66.9 ± 2.9 ± 4.4 mb, where the first uncertainty is experimental and the second is
due to the extrapolation
Measurement of the Z+b-jet cross-section in pp collisions at √s = 7 TeV in the forward region
The associated production of a Z boson or an off-shell photon γ
∗ with a bottom
quark in the forward region is studied using proton-proton collisions at a centre-of-mass energy
of 7 TeV. The Z bosons are reconstructed in the Z/γ∗ → µ
+µ
− final state from muons
with a transverse momentum larger than 20 GeV, while two transverse momentum thresholds
are considered for jets (10 GeV and 20 GeV). Both muons and jets are reconstructed
in the pseudorapidity range 2.0 < η < 4.5. The results are based on data corresponding
to 1.0 fb−1
recorded in 2011 with the LHCb detector. The measurement of the Z+b-jet
cross-section is normalized to the Z+jet cross-section. The measured cross-sections are
σ(Z/γ∗
(µ
+µ
−) + b-jet) = 295 ± 60 (stat) ± 51 (syst) ± 10 (lumi) fb (0.1)
for pT(jet) > 10 GeV, and
σ(Z/γ∗
(µ
+µ
−) + b-jet) = 128 ± 36 (stat) ± 22 (syst) ± 5 (lumi) fb (0.2)
for pT(jet) > 20 GeV
Study of η − η′ mixing from measurement of B (s) 0 → J/ψη(′) decay rates
A study of B and B0
s meson decays into J/ψη and J/ψη0 final states is performed
using a data set of proton-proton collisions at centre-of-mass energies of 7 and 8 TeV,
collected by the LCHb experiment and corresponding to 3.0 fb−1
of integrated luminosity.
The decay B0 → J/ψη0
is observed for the first time. The following ratios of branching
fractions are measured:
B(B0 → J/ψη0
)
B(B0
s → J/ψη0)
= (2.28 ± 0.65 (stat) ± 0.10 (syst) ± 0.13 (fs/fd)) × 10−2
,
B(B0 → J/ψη)
B(B0
s → J/ψη)
= (1.85 ± 0.61 (stat) ± 0.09 (syst) ± 0.11 (fs/fd)) × 10−2
,
where the third uncertainty is related to the present knowledge of fs/fd, the ratio between
the probabilities for a b quark to form a B0
s or a B0 meson. The branching fraction ratios
are used to determine the parameters of η−η
0 meson mixing. In addition, the first evidence
for the decay B0
s → ψ(2S)η
0
is reported, and the relative branching fraction is measured,
B(B0
s → ψ(2S)η
0
)
B(B0
s → J/ψη0)
= (38.7 ± 9.0 (stat) ± 1.3 (syst) ± 0.9(B)) × 10−2
,
where the third uncertainty is due to the limited knowledge of the branching fractions of
J/ψ and ψ(2S) mesons
Search for long-lived particles decaying to jet pairs
A search is presented for long-lived particles with a mass between 25 and 50 GeV/c2 and a lifetime between 1 and 200ps in a sample of proton–proton collisions at a centre-of-mass energy of s√=7 TeV, corresponding to an integrated luminosity of 0.62 fb −1, collected by the LHCb detector. The particles are assumed to be pair-produced by the decay of a standard model-like Higgs boson. The experimental signature of the long-lived particle is a displaced vertex with two associated jets. No excess above the background is observed and limits are set on the production cross-section as a function of the long-lived particle mass and lifetime