1,307 research outputs found
Intrinsic structure of two-phonon states in the interacting boson model
A general study of excitations up to two-phonon states is carried out using
the intrinsic-state formalism of the Interacting Boson Model (IBM). Spectra and
transitions for the different dynamical symmetries are analyzed and the
correspondence with states in the laboratory frame is established. The
influence of multi-phonon states is discussed. The approach is useful in
problems where the complexity of the IBM spectrum renders the analysis in the
laboratory frame difficult.Comment: 22 pages, TeX (ReVTeX). 7 eps figures. Submitted to Nucl. Phys.
Biomecánica aplicada en el tejo como disciplina deportiva.
Este artículo analiza el tejo como disciplina deportiva y algunas variables biomecánicas: centro de gravedad del deportista, ángulo de tiro, fuerza de impulso y velocidad de lanzamiento del tejo, mediciones hechas utilizando métodos de investigación biomecánicas tradicionales como la medición del centro de gravedad según Bernstein y Ficher,[1] técnicas cinematográficas y métodos dinamográficos, en los cuales se utilizaron dispositivos como cámaras de video, fotoceldas [2], celdas de carga y galgas extensiométricas [2], dispositivos asociados a circuitos electrónicos que permiten una alta fiabilidad de los resultados, ya que es el primer estudio que se hace a este nivel en esta práctica deportiva
Smart Nanoparticles as Advanced Anti-Akt Kinase Delivery Systems for Pancreatic Cancer Therapy
Pancreatic cancer is one of the deadliest cancers partly due to late diagnosis, poor drug delivery to the target site, and acquired resistance to therapy. Therefore, more effective therapies are urgently needed to improve the outcome of patients. In this work, we have tested self-assembling genetically engineered polymeric nanoparticles formed by elastin-like recombinamers (ELRs), carrying a small peptide inhibitor of the protein kinase Akt, in both PANC-1 and patient-derived pancreatic cancer cells (PDX models). Nanoparticle cell uptake was measured by flow cytometry, and subcellular localization was determined by confocal microscopy, which showed a lysosomal localization of these nanoparticles. Furthermore, metabolic activity and cell viability were significantly reduced after incubation with nanoparticles carrying the Akt inhibitor in a time- and dose-dependent fashion. Self-assembling 73 ± 3.2 nm size nanoparticles inhibited phosphorylation and consequent activation of Akt protein, blocked the NF-κB signaling pathway, and triggered caspase 3-mediated apoptosis. Furthermore, in vivo assays showed that ELR-based nanoparticles were suitable devices for drug delivery purposes with long circulating time and minimum toxicity. Hence, the use of these smart nanoparticles could lead to the development of more effective treatment options for pancreatic cancer based on the inhibition of Akt
Spectral Distribution Complexity of the Surface Fibrillatory Waves Predicts Post-Catheter Ablation Relapse in Persistent Atrial Fibrillation
As for most of cardiac arrhythmias, atrial fibrillation (AF) is primarily
treated by catheter ablation (CA). However, the mid-term recurrence rate of
this procedure in persistent AF patients is still limited and the preoperative
prediction of its outcome is clinically interesting to select candidates who
could benefit the most from the intervention. This context encouraged the study
of C0 complexity as a novel predictor, because it estimates organization of the
power spectral distribution (PSD) of the fibrillatory waves (f-waves). For that
purpose, the PSD was divided into two divergent components using a threshold,
theta, which was considered by multiplying the mean value of the PSD by a
factor, alpha, ranging between 1.5 and 2.5. On a database of 74 patients, the
values of C0 complexity computed for all alpha factors reported statistically
significant differences between the patients who maintained sinus rhythm and
those who relapsed to AF after a follow-up of 9 months. They also showed higher
values of sensitivity (Se), specificity (Sp), and accuracy (Acc) than the well
known predictors of the dominant frequency (DF) and f-wave amplitude. Moreover,
the combination of the DF and the C0 complexity computed with alpha = 2, via a
decision tree, improved classification until values of Se, Sp and Acc of 75.33,
77.33 and 76.58%, respectively. These results manifests the relevance of the
f-wave PSD distribution to anticipate CA outcome in persistent AF patients
Energy conversion theorems for some linear steady-states
One of the main issues that real energy converters present, when they produce
effective work, is the inevitable entropy production. Within the context of
Non-equilibrium Thermodynamics, entropy production tends to energetically
degrade man-made or living systems. On the other hand, it is also not useful to
think about designing an energy converter that works in the so-called minimum
entropy production regime since the effective power output and efficiency are
zero. In this manuscript, we establish some \textit{Energy Conversion Theorems}
similar to Prigogine's one with constrained forces, their purpose is to reveal
trade-offs between design and the so-called operation modes for
--linear isothermal energy converters. The objective
functions that give rise to those thermodynamic constraints show stability. A
two--meshes electric circuit was built as an example to demonstrate the
Theorems' validity. Likewise, we reveal a type of energetic hierarchy for power
output, efficiency and dissipation function when the circuit is tuned to any of
the operating regimes studied here: maximum power output (), maximum
efficient power (), maximum omega function (), maximum
ecological function (), maximum efficiency () and minimum
dissipation function ().Comment: 33 pages, 15 figures, 2 table
- …