3,120 research outputs found
Synthesizing attractors of Hindmarsh-Rose neuronal systems
In this paper a periodic parameter switching scheme is applied to the
Hindmarsh-Rose neuronal system to synthesize certain attractors. Results show
numerically, via computer graphic simulations, that the obtained synthesized
attractor belongs to the class of all admissible attractors for the
Hindmarsh-Rose neuronal system and matches the averaged attractor obtained with
the control parameter replaced with the averaged switched parameter values.
This feature allows us to imagine that living beings are able to maintain vital
behavior while the control parameter switches so that their dynamical behavior
is suitable for the given environment.Comment: published in Nonlinear Dynamic
Using Green Fluorescent Protein to Correlate Temperature and Fluorescence Intensity into Bacterial Systems
The unique and stunning spectroscopic properties of Green Fluorescent Protein (GFP) from the jellyfish Aequorea victoria, not to mention of its remarkable structural stability, have made it one of the most widely studied and used molecular tool in medicine, biochemistry, and cell biology. Its high fluorescent quantum yield is due to its chromophore, structure responsible of emitting green visible light when excited at 395 nm. Although it is noteworthy that there is enormous available information of the wonderful luminescent properties of GFP, the fact is that there are features and properties unexplored yet, particulary about its capabilities as molecular reporter in several biological processes. In this work, we used recombinant DNA technology to express the protein in bacteria; prepared the bacterial system both in liquid and solid media, and assembled an experimental set to expose those media to a laser beam; thereby we excited the protein chromophore and used emission spectroscopy in order to observe variations in fluorescence when the bacterial system is exposed to different temperatures
Determinación reciente de la colesterolemia en población adulta sana de Pamplona
RESUMEN: Objetivo: Los objetivos del estudio fueron estimar la proporción de la población adulta sana de Pamplona que había determinado recientemente su colesterolemia e identificar los factores asociados a
esta determinación.
Métodos: Estudio transversal con entrevista personal a 1066 habitantes de Pamplona seleccionados por muestreo de rutas aleatorias. Se estratificó la ciudad
en tres áreas urbanas según el nivel socioeconómico (alto, medio, bajo). La participación fue de un 91,8%.
Utilizando como variable dependiente la determinación del colesterol total en los últimos 5 años, y como variables independientes la edad, el sexo, el
nivel socioeconómico y el hábito tabáquico, se calcularon las odds ratios (OR) univariantes y se ajustó un modelo de regresión logística.
Resultados: El 71,2% de la muestra estudiada (IC 95%: 68,3-74,O) se había determinado el colesterol en los últimos cinco años. Los no fumadores conocían más su colesterolemia que los fumadores con una OR ajustada de 1,38 (IC 95%: 1 ,O-1,9); los hombres lo conocían más que las mujeres (OR ajustada de 1,5; IC
95% 1,l-2,O). El conocimiento era menos frecuente en el grupo de edad 30 años. La determinación de la colesterolemia se daba más en los individuos de nivel socioeconómico medio y alto (OR ajustadas 3,2; IC 95% 2,2-4,7 y 1,6; IC 95% 1,l-2,3), respectivamente.
Conclusiones: La determinación reciente del
colesterol era más frecuente en individuos de mayor edad y en varones. La determinación de la colesterolemia era menos frecuente en algunos grupos con peor perfil de riesgo coronario (menor nivel socioeconómico
y fumadores). Estos resultados sugieren la necesidad de intervenciones para mejorar el conocimientoy control de la colesterolemia en adultos sanos
Confronting Spin Flavor Solutions of the Solar Neutrino Problem with current and future solar neutrino data
We show that spin flavor precession solutions to the solar neutrino problem,
although preferred by the latest solar data, are ruled out by the first results
from the KamLAND reactor experiment, at more than 3_sigma. An illustrative chi2
plot comparing these descriptions with oscillations is given.Comment: new appendix added discussing the impact of the KamLAND data. This
updates the one published in Phys.Rev.D66:093009,200
Effects of Low-Energy Laser Irradiation on Sperm Cells Dynamics of Rabbit (Oryctolagus Cuniculus)
Infertility is a world disease in which a couple is unable to achieve pregnancy. There are numerous parameters to determinate fertility; nevertheless, sperm motility is by consensus one of the most important attributes to evaluate male fertility. Contributions to a better understanding of this crucial parameter are imperative; hence, the aim of this investigation was to assess the effect of low-energy laser irradiation on sperm cell dynamics in thawed samples that were cryopreserved. We used a 405 nm blue laser beam to irradiate spermatic cells from rabbit inside a temperature-controlled dispersion chamber at 37 °C; then, we applied an image recognizing system to calculate individual sperm trajectories and velocities. We found that sperms raise its motility after irradiation suggesting that λ=405 nm is an optimal wavelength for spermatic photo-stimulation
Effects of Postmortem Aging Time and Muscle Location on Objective Measures of Semitendinosus Steak Tenderness
Beef tenderness is the most important trait affecting consumer beef eating satisfaction. Cuts from muscles with superior tenderness (tenderloin, ribeye, striploin) are consequently most highly valued, but because of recent record-high beef prices, the need to identify more economical cuts that will meet consumer expectations for tenderness is greater than ever. The eye of round (Semitendinosus) has traditionally been marketed as a lower-value cut, primarily owing to its inherent toughness. Tenderness improves throughout postmortem aging and continues to improve in muscles aged for greater than 35 days. Retail steaks from the Semitendinosus receive, on average, 17 days of aging, with almost half (48.5%) receiving less than 14 days. This indicates a significant opportunity for tenderness improvement of Semitendinosus steaks through extended aging times.
In many muscles, including the Longissimus, tenderness depends on anatomical location. Tenderness is often reduced in regions of the muscle closest to the ends or in close proximity to heavy connective tissue seams. Very little is known about the effects of aging and anatomical location on the tenderness of the Semitendinosus.
Warner-Bratzler shear force testing is commonly used to measure beef tenderness objectively. Consumers rate beef with shear values of 9.5 lb as “tender,” so if tenderness of Semitendinosus steaks can be improved to meet this threshold, then the eye of round may offer a suitable alternative to higher-valued cuts for consumers and an opportunity for increased value for processors. Thus, the objectives of this study were to evaluate the effects of aging and anatomical location on the tenderness of Semitendinosus steaks
Self-Assembly of Amphiphilic Dendrimers: The Role of Generation and Alkyl Chain Length in siRNA Interaction
Citation: Marquez-Miranda, V., Araya-Duran, I., Camarada, M. B., Comer, J., Valencia-Gallegos, J. A., & Gonzalez-Nilo, F. D. (2016). Self-Assembly of Amphiphilic Dendrimers: The Role of Generation and Alkyl Chain Length in siRNA Interaction. Scientific Reports, 6, 15. https://doi.org/10.1038/srep29436An ideal nucleic-acid transfection system should combine the physical and chemical characteristics of cationic lipids and linear polymers to decrease cytotoxicity and uptake limitations. Previous research described new types of carriers termed amphiphilic dendrimers (ADs), which are based on polyamidoamine dendrimers (PAMAM). These ADs display the cell membrane affinity advantage of lipids and preserve the high affinity for DNA possessed by cationic dendrimers. These lipid/dendrimer hybrids consist of a low-generation, hydrophilic dendron (G2, G1, or G0) bonded to a hydrophobic tail. The G2-18C AD was reported to be an efficient siRNA vector with significant gene silencing. However, shorter tail ADs (G2-15C and G2-13C) and lower generation (G0 and G1) dendrimers failed as transfection carriers. To date, the self-assembly phenomenon of this class of amphiphilic dendrimers has not been molecularly explored using molecular simulation methods. To gain insight into these systems, the present study used coarse-grained molecular dynamics simulations to describe how ADs are able to self-assemble into an aggregate, and, specifically, how tail length and generation play a key role in this event. Finally, explanations are given for the better efficiency of G2/18-C as gene carrier in terms of binding of siRNA. This knowledge could be relevant for the design of novel, safer ADs with well-optimized affinity for siRNA
Probing neutrino non-standard interactions with atmospheric neutrino data
We have reconsidered the atmospheric neutrino anomaly in light of the laetst
data from Super-Kamiokande contained events and from Super-Kamiokande and MACRO
up-going muons. We have reanalysed the proposed solution to the atmospheric
neutrino anomaly in terms of non-standard neutrino-matter interactions (NSI) as
well as the standard nu_mu -> nu_tau oscillations (OSC). Our statistical
analysis shows that a pure NSI mechanism is now ruled out at 99%, while the
standard nu_mu -> nu_tau OSC mechanism provides a quite remarkably good
description of the anomaly. We therefore study an extended mechanism of
neutrino propagation which combines both oscillation and non-standard
neutrino-matter interactions, in order to derive limits on flavour-changing
(FC) and non-universal (NU) neutrino interactions. We obtain that the
off-diagonal flavour-changing neutrino parameter epsilon and the diagonal
non-universality neutrino parameter epsilon' are confined to -0.03 < epsilon <
0.02 and |epsilon'| < 0.05 at 99.73% CL. These limits are model independent and
they are obtained from pure neutrino-physics processes. The stability of the
neutrino oscillation solution to the atmospheric neutrino anomaly against the
presence of non-standard neutrino interactions establishes the robustness of
the near-maximal atmospheric mixing and massive-neutrino hypothesis. The best
agreement with the data is obtained for Delta_m^2 = 2.3*10^{-3} eV^2,
sin^2(2*theta) = 1, epsilon = 6.7*10^{-3} and epsilon' = 1.1*10^{-3}, although
the chi^2 function is quite flat in the epsilon and epsilon' directions for
epsilon, epsilon' -> 0.Comment: 26 pages, LaTeX file using REVTeX4, 1 table and 12 figures included.
Added a revised analysis which takes into account the new 1489-day
Super-Kamiokande and final MACRO data. The bound on NSI parameters is
considerably improve
Constraining neutrino oscillation parameters with current solar and atmospheric data
We analyze the impact of recent solar, atmospheric and reactor data in the
determination of the neutrino oscillation parameters, taking into account that
both the solar nu_e and the atmospheric nu_mu may convert to a mixture of
active and sterile neutrinos. We use the most recent global solar neutrino
data, including the 1496-day Super-K neutrino data sample, and we investigate
in detail the impact of the SNO neutral current, spectral and day/night data by
performing also an analysis using only the charged current rate from SNO. The
implications of the first 145.1 days of KamLAND data on the determination of
the solar neutrino parameters are also discussed in detail. We confirm the
clear preference of solar+reactor data for the pure active LMA-MSW solution of
the solar neutrino problem, and obtain that the LOW, VAC, SMA and Just-So^2
solutions are disfavored with a Delta_chi^2 = 22, 22, 36, 44, respectively.
Furthermore, we find that the global solar data constrains the admixture of a
sterile neutrino to be less than 43% at 99% CL. By performing an improved fit
of the atmospheric data, we also update the corresponding regions of
oscillation parameters. We find that the recent atmospheric Super-K (1489-day)
and MACRO data have a strong impact on constraining a sterile component in
atmospheric oscillations: if the nu_mu is restricted to the atmospheric mass
states only a sterile admixture of 16% is allowed at 99% CL, while a bound of
35% is obtained in the unconstrained case. Pure sterile oscillations are
disfavored with a Delta_chi^2 = 34.6 compared to the pure active case.Comment: 28 pages, LaTeX file using RevTEX4, 12 figures and 3 tables included.
Improved version including the new KamLAND dat
MSW mediated neutrino decay and the solar neutrino problem
We investigate the solar neutrino problem assuming simultaneous presence of
MSW transitions in the sun and neutrino decay on the way from sun to earth. We
do a global -analysis of the data on total rates in Cl, Ga and
Superkamiokande (SK) experiments and the SK day-night spectrum data and
determine the changes in the allowed region in the \dm - \tan^2\theta plane
in presence of decay. We also discuss the implications for unstable neutrinos
in the SNO experiment.Comment: Final version to appear in Phys. Rev.
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