338 research outputs found
Deaths due to oral cancer in Chile in the period 2002-2012
Indexación: Scopus; Scielo.Background: Oral cancer is the 15th most common cause of cancer death in the world. In Chile, 1% of all cancer deaths are related to oral and pharyngeal cancer. Aim: To determine mortality rates for oral cancer in Chile and its regions between 2002-2012. Material and Methods: Deaths and their causes between the years 2002-2012 were obtained from the Chilean National Statistics Institute. Crude and adjusted rates by age and sex were calculated for the country and its regions. The denominator was Chilean population on June 30, 2012 and the WHO standard population. Results: In the period studied, 1,611 individuals with a mean age of 67.6 years (63% men) died because of oral cancer. The most common location of the tumor was the tongue in 27% of cases and the parotid gland in 16%. The adjusted mortality rate in Chile was 0.85/100,000 inhabitants (1.13 and 0.58 in men and women, respectively). The regions with the highest rates were Antofagasta (1.51), Aysén (1.22) and Magallanes (1.17). Deaths among men occurred at younger ages than women. Conclusions: Mortality rates due to oral cancer in Chile are lower than abroad. The highest rates observed in some regions may be influenced by environmental factors such as arsenic contamination in Antofagasta and the lack of specialists and specialized care centers in Aysén and Magallanes. © 2018, Sociedad Medica de Santiago. All rights reserved.https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872018000400487&lng=en&nrm=iso&tlng=e
Homobivalent Lamellarin-Like Schiff Bases: In Vitro Evaluation of Their Cancer Cell Cytotoxicity and Multitargeting Anti-Alzheimer's Disease Potential
Marine alkaloids belonging to the lamellarins family, which incorporate a 5,6-dihydro-1-phenylpyrrolo[2,1-a]isoquinoline (DHPPIQ) moiety, possess various biological activities, spanning from antiviral and antibiotic activities to cytotoxicity against tumor cells and the reversal of multidrug resistance. Expanding a series of previously reported imino adducts of DHPPIQ 2-carbaldehyde, novel aliphatic and aromatic Schiff bases were synthesized and evaluated herein for their cytotoxicity in five diverse tumor cell lines. Most of the newly synthesized compounds were found noncytotoxic in the low micromolar range (<30 μM). Based on a Multi-fingerprint Similarity Search aLgorithm (MuSSeL), mainly conceived for making protein drug target prediction, some DHPPIQ derivatives, especially bis-DHPPIQ Schiff bases linked by a phenylene bridge, were prioritized as potential hits addressing Alzheimer's disease-related target proteins, such as cholinesterases (ChEs) and monoamine oxidases (MAOs). In agreement with MuSSeL predictions, homobivalent para-phenylene DHPPIQ Schiff base 14 exhibited a noncompetitive/mixed inhibition of human acetylcholinesterase (AChE) with Ki in the low micromolar range (4.69 μM). Interestingly, besides a certain inhibition of MAO A (50% inhibition of the cell population growth (IC50) = 12 μM), the bis-DHPPIQ 14 showed a good inhibitory activity on self-induced β-amyloid (Aβ)1-40 aggregation (IC50 = 13 μM), which resulted 3.5-fold stronger than the respective mono-DHPPIQ Schiff base 9
Cosmic ray spectrum and anisotropies from the knee to the second knee
We consider the scenario in which the knee in the cosmic ray spectrum is due
to a change in the escape mechanism of cosmic rays from the Galaxy from one
dominated by transverse diffusion to one dominated by drifts. We show that this
scenario explains not only the changes in spectral slope at the knee and at the
second knee, but can also account for the main characteristics of the observed
energy dependent anisotropy amplitude and phase of first harmonic in the energy
range between and eV. This provides a useful handle to
distinguish this diffusion/drift model from other scenarios proposed to explain
the knee in the spectrum.Comment: 13 pages, 3 figures; revised version with minor changes. To appear in
JCA
Comparative study of an Eden model for the irreversible growth of spins and the equilibrium Ising model
The Magnetic Eden Model (MEM) with ferromagnetic interactions between
nearest-neighbor spins is studied in dimensional rectangular geometries
for . In the MEM, magnetic clusters are grown by adding spins at the
boundaries of the clusters. The orientation of the added spins depends on both
the energetic interaction with already deposited spins and the temperature,
through a Boltzmann factor. A numerical Monte Carlo investigation of the MEM
has been performed and the results of the simulations have been analyzed using
finite-size scaling arguments. As in the case of the Ising model, the MEM in is non-critical (only exhibits an ordered phase at ). In
the MEM exhibits an order-disorder transition of second-order at a finite
temperature. Such transition has been characterized in detail and the relevant
critical exponents have been determined. These exponents are in agreement
(within error bars) with those of the Ising model in 2 dimensions. Further
similarities between both models have been found by evaluating the probability
distribution of the order parameter, the magnetization and the susceptibility.
Results obtained by means of extensive computer simulations allow us to put
forward a conjecture which establishes a nontrivial correspondence between the
MEM for the irreversible growth of spins and the equilibrium Ising model. This
conjecture is certainly a theoretical challenge and its confirmation will
contribute to the development of a framework for the study of irreversible
growth processes.Comment: 21 pages, 11 figure
A study on the sharp knee and fine structures of cosmic ray spectra
The paper investigates the overall and detailed features of cosmic ray (CR)
spectra in the knee region using the scenario of nuclei-photon interactions
around the acceleration sources. Young supernova remnants can be the physical
realities of such kind of CR acceleration sites. The results show that the
model can well explain the following problems simultaneously with one set of
source parameters: the knee of CR spectra and the sharpness of the knee, the
detailed irregular structures of CR spectra, the so-called "component B" of
Galactic CRs, and the electron/positron excesses reported by recent
observations. The coherent explanation serves as evidence that at least a
portion of CRs might be accelerated at the sources similar to young supernova
remnants, and one set of source parameters indicates that this portion mainly
comes from standard sources or from a single source.Comment: 13 pages, 4 figures, accepted for publication in SCIENCE CHINA
Physics, Mechanics & Astronomy
Superprocesses as models for information dissemination in the Future Internet
Future Internet will be composed by a tremendous number of potentially
interconnected people and devices, offering a variety of services, applications
and communication opportunities. In particular, short-range wireless
communications, which are available on almost all portable devices, will enable
the formation of the largest cloud of interconnected, smart computing devices
mankind has ever dreamed about: the Proximate Internet. In this paper, we
consider superprocesses, more specifically super Brownian motion, as a suitable
mathematical model to analyse a basic problem of information dissemination
arising in the context of Proximate Internet. The proposed model provides a
promising analytical framework to both study theoretical properties related to
the information dissemination process and to devise efficient and reliable
simulation schemes for very large systems
Results from the KASCADE, KASCADE-Grande, and LOPES experiments
The origin of high-energy cosmic rays in the energy range from 10^14 to 10^18
eV is explored with the KASCADE and KASCADE-Grande experiments. Radio signals
from air showers are measured with the LOPES experiment. An overview on results
is given.Comment: Talk at The ninth International Conference on Topics in Astroparticle
and Underground Physics, TAUP 2005, Zaragoza, September 10-14, 200
Anomalous behavior of the irreversible magnetization and time relaxation in YBaCuO single crystals with splayed tracks
We have studied the angular dependence of the irreversible magnetization and
its time relaxation in YBaCuO single crystals with one or two
families of columnar defects inclined with respect to the c-axis. At high
magnetic fields, the magnetization shows the usual maximum centered at the mean
tracks' orientation and an associated minimum in the normalized relaxation
rate. In contrast, at low fields we observe an anomalous local minimum in the
magnetization and a maximum in the relaxation rate. We present a model to
explain this anomaly based on the slowing down of the creep processes arising
from the increase of the vortex-vortex interactions as the applied field is
tilted away from the mean tracks' direction.Comment: 15 pages, 6 figures. Submitted to Phys. Rev .
- …