559 research outputs found
Curves in quantum state space, geometric phases, and the brachistophase
Given a curve in quantum spin state space, we inquire what is the relation
between its geometry and the geometric phase accumulated along it. Motivated by
Mukunda and Simon's result that geodesics (in the standard Fubini-Study metric)
do not accumulate geometric phase, we find a general expression for the
derivatives (of various orders) of the geometric phase in terms of the
covariant derivatives of the curve. As an application of our results, we put
forward the brachistophase problem: given a quantum state, find the
(appropriately normalized) hamiltonian that maximizes the accumulated geometric
phase after time - we find an analytical solution for all spin values,
valid for small . For example, the optimal evolution of a spin coherent
state consists of a single Majorana star separating from the rest and tracing
out a circle on the Majorana sphere.Comment: 23 pages, 6 figure
Desarrollo de emulsiones con aceite esencial de naranja formuladas con diferentes biopolímeros.
Recientemente se ha presentado un gran interés en la industria alimenticia y en la medicina preventiva por la búsqueda de antioxidantes naturales, principalmente obtenidos de extractos vegetales; actualmente se considera un antioxidante natural el aceite esencial de naranja, sin embargo, a la vez es muy inestable a ciertos factores ambientales como luz, oxígeno, humedad, pH, etc.; una manera de proteger la degradación es por medio de una emulsión. El propósito de este estudio fue desarrollar emulsiones de aceite esencial de naranja utilizando β-ciclodextrina, concentrado de proteína de suero y goma xantana. Las combinaciones de los biopolímeros fue de 0, 0.1, 0.15, 0.2, 0.25, 0.3, 0.4, 0.5, 0.8, 0.85, 0.9, 1 %, realizándose 10 fórmulas de emulsiones (identificadas como 1 a 10). El análisis de tamaño de partícula nos proporcionó un diámetro promedio superficial [D3,2] y diámetro promedio volumetrico [D 4,3] de 1.6 y 2 μm respectivamente. Se obtuvó la tasa de coalesencia de las emulsiones de 1.35x10-8 a 9.13 x10-9, en las emulsiones 1, 2, 6, 7, 8 y 9. Siendo estables solo 6 fórmulas y presentarse 4 inestables, de las cuales presentaron índices de cremado entre 15-40 %. Este estudio mostró que βCD, WPC, y XG son factibles para el uso como materiales de pared en las formulaciones de emulsiones para el aceite esencial de naranja
Factores que influyen en la composicón de ácidos grasos destilados de soya (Glycine Max L.)
El aceite de soya es el más usado a nivel mundial, con un 54% del consumo, por lo que la alta producción de éste genera altas cantidades de subproductos. En la industria de extracción y refinación, una demanda actual es la disminución y/o aprovechamiento de éstos, lo que requiere investigación enfocada a su caracterización. Durante la deodorización, se genera un subproducto conocido como ácidos grasos destilados (AGD´s) del cual se reporta alto contenido de componentes menores como fitoesteroles, tocoferoles y escualeno, con actividad biológica como antiinflamatorios, antioxidantes, anticancerígenos e inhibidores de la absorción del colesterol a nivel intestinal, lo cual les da un alto valor en la industria alimentaria. En este trabajo se determinó la influencia de los factores año de cosecha, grado de calidad y procedencia de la oleoginosa en la concentración de fitoesteroles, tocoferoles y escueleno, concluyendo que la concentración de dichos compuestos en los AGD´s, varía en función del origen de la oleaginosa, año de ¿cosecha y no así por el grado de calidad del aceite
Caracterización tecnofuncional de harinas obtenidas de la cascara y semillas de pepino (Cucumis sativus) y su aplicación en un alimento funcional.
En la actualidad surge la idea de utilizar las frutas en forma de harina como una alternativa de ingrediente funcional. El objetivo del presente trabajo fue caracterizar las propiedades bromatológicas y funcionales harinas de cascara y semillas de pepino obtenidas como subproducto. En general se observan diferencias estadísticamente significativas entre ambas harinas de cascara y semillas obtenidas a partir de pepino, destacando el contenido proteico de 16.24 ± 0.320 y 20.42 ± 0.244% respectivamente y de fibra 17.29±0.990 y 27.91±0.088% respectivamente de ambas harinas por ende podrían utilizarse como ingrediente funcional en la realización de distintos alimentos, se realizaron galletas horneadas a partir de la harina de cascara de pepino debido al contenido de humedad de esta, y se obtuvieron características organolépticas aceptables
3D Spectroscopy of Local Luminous Compact Blue Galaxies: Kinematics of NGC 7673
The kinematic properties of the ionized gas of local Luminous Compact Blue
Galaxy (LCBG) NGC 7673 are presented using three dimensional data taken with
the PPAK integral field unit at the 3.5-m telescope in the Centro Astron\'omico
Hispano Alem\'an. Our data reveal an asymmetric rotating velocity field with a
peak to peak difference of 60 km s. The kinematic centre is found to be
at the position of a central velocity width maximum ( km
s), which is consistent with the position of the luminosity-weighted
centroid of the entire galaxy. The position angle of the minor rotation axis is
168 as measured from the orientation of the velocity field contours.
At least two decoupled kinematic components are found. The first one is compact
and coincides with the position of the second most active star formation region
(clump B). The second one is extended and does not have a clear optical
counterpart. No evidence of active galactic nuclei activity or supernovae
galactic winds powering any of these two components has been found. Our data,
however, show evidence in support of a previously proposed minor merger
scenario in which a dwarf galaxy, tentatively identified with clump B, is
falling into NGC 7673. and triggers the starburst. Finally, it is shown that
the dynamical mass of this galaxy may be severely underestimated when using the
derived rotation curve or the integrated velocity width, under the assumption
of virialization.Comment: Accepted for publication by MNRAS. The paper contains 10 figures and
2 table
Risk perception of medicinal marijuana in medical students from northeast Mexico [version 1; referees: awaiting peer review]
Background. Several studies have shown support from the public toward the use of medicinal marijuana. In this cross-sectional study, we assess the risk
perception to medicinal marijuana in a sample of medical students. Methods. To estimate risk perception, a visual scale that ranges from 0 cm (without risk) to 10 cm (totally risky) was used. Risk
perception was expressed as the median of the cm marked over the scale. Differences among groups was tested with the Mann-Whitney and Kruskal-Wallis tests, as appropriate.
Results. 283 students participated in the study. Risk perception to medicinal
marijuana was 4.22, paracetamol 1.56 and sedatives 5.0. A
significant difference in risk perception was observed in those that self-reported to smoke
and consume alcohol.
Conclusions. Risk perception of medicinal marijuana is 4.22 in medical students of northeast of Mexico. Students may underestimate its adverse
effects. More studies with respect to this are needed
FeCo Nanowire-Strontium Ferrite Powder Composites for Permanent Magnets with High-Energy Products
Due to the issues associated with rare-earth elements, there arises a strong
need for magnets with properties between those of ferrites and rare-earth
magnets that could substitute the latter in selected applications. Here, we
produce a high remanent magnetization composite bonded magnet by mixing FeCo
nanowire powders with hexaferrite particles. In the first step, metallic
nanowires with diameters between 30 and 100 nm and length of at least 2 {\mu}m
are fabricated by electrodeposition. The oriented as-synthesized nanowires show
remanence ratios above 0.76 and coercivities above 199 kA/m and resist core
oxidation up to 300 {\deg}C due to the existence of a > 8 nm thin oxide
passivating shell. In the second step, a composite powder is fabricated by
mixing the nanowires with hexaferrite particles. After the optimal nanowire
diameter and composite composition are selected, a bonded magnet is produced.
The resulting magnet presents a 20% increase in remanence and an enhancement of
the energy product of 48% with respect to a pure hexaferrite (strontium
ferrite) magnet. These results put nanowire-ferrite composites at the forefront
as candidate materials for alternative magnets for substitution of rare earths
in applications that operate with moderate magnet performance
Desarrollo de bebidas funcionales adicionadas con α-tocoferol y aceites esenciales de limón y toronja por medio de una nanoemulsión múltiple (w1/o/w2).
La industria de bebidas en México, experimenta una creciente demanda de nuevos productos con propiedadesfuncionales. El objetivo de este trabajo fue desarrollar una nanoemulsion múltiple w1/o/w2 con propiedades antioxidantes otorgadas por el α-Tocoferol y los aceites esenciales de toronja y limón e incorporarla a una bebida natural a base de frutas e incorporación de una fibra soluble. En este caso inulina destaca por sus propiedades prebióticas. Se lograron obtener nanoemulsiones estables debido a la adición de una proteína en la fase acuosa externa, ya que se disminuye el tamaño de partícula que contribuyó a mejorar la estabilidad de la nanoemulsión doble esto concuerda con los valores obtenidos de tasa de coalescencia, mayores a 1x10-6, así mismo las nanoemulsión presentó alta actividad antioxidante. La densidad y el pH no variaron respecto al tiempo. Se logró la estabilidad de la nanoemulsión en la bebida, gracias a que la densidad fue muy cercana a la del agua. Los resultados obtenidos sugieren que es factible la adición de nanoemulsiones para incorporarse en bebidas con antioxidantes encapsulados, contribuyendo en el sabor y aroma en bebidas, usando aceites esenciales
Does native Trypanosoma cruzi calreticulin mediate growth inhibition of a mammary tumor during infection?
Indexación: Web of Science.Background: For several decades now an antagonism between Trypanosoma cruzi infection and tumor development has been detected. The molecular basis of this phenomenon remained basically unknown until our proposal that T. cruzi Calreticulin (TcCRT), an endoplasmic reticulum-resident chaperone, translocated-externalized by the parasite, may mediate at least an important part of this effect. Thus, recombinant TcCRT (rTcCRT) has important in vivo antiangiogenic and antitumor activities. However, the relevant question whether the in vivo antitumor effect of T. cruzi infection is indeed mediated by the native chaperone (nTcCRT), remains open. Herein, by using specific modified anti-rTcCRT antibodies (Abs), we have neutralized the antitumor activity of T. cruzi infection and extracts thereof, thus identifying nTcCRT as a valid mediator of this effect.
Methods: Polyclonal anti-rTcCRT F(ab')(2) Ab fragments were used to reverse the capacity of rTcCRT to inhibit EAhy926 endothelial cell (EC) proliferation, as detected by BrdU uptake. Using these F(ab')(2) fragments, we also challenged the capacity of nTcCRT, during T. cruzi infection, to inhibit the growth of an aggressive mammary adenocarcinoma cell line (TA3-MTXR) in mice. Moreover, we determined the capacity of anti-rTcCRT Abs to reverse the antitumor effect of an epimastigote extract (EE). Finally, the effects of these treatments on tumor histology were evaluated.
Results: The rTcCRT capacity to inhibit ECs proliferation was reversed by anti-rTcCRT F(ab')(2) Ab fragments, thus defining them as valid probes to interfere in vivo with this important TcCRT function. Consequently, during infection, these Ab fragments also reversed the in vivo experimental mammary tumor growth. Moreover, anti-rTcCRT Abs also neutralized the antitumor effect of an EE, again identifying the chaperone protein as an important mediator of this anti mammary tumor effect. Finally, as determined by conventional histological parameters, in infected animals and in those treated with EE, less invasive tumors were observed while, as expected, treatment with F(ab')(2) Ab fragments increased malignancy.
Conclusion: We have identified translocated/externalized nTcCRT as responsible for at least an important part of the anti mammary tumor effect of the chaperone observed during experimental infections with T. cruzi.http://bmccancer.biomedcentral.com/articles/10.1186/s12885-016-2764-
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